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Downloaded from : uptukhabar.net DGI Greater Noida Lecture Notes-Module Wise Programming for Problem Solving (KCS-101/KCS-201) DGI Greater Noida INDEX S.No...

Downloaded from : uptukhabar.net DGI Greater Noida Lecture Notes-Module Wise Programming for Problem Solving (KCS-101/KCS-201) DGI Greater Noida INDEX S.No Topic/Syllabus Page Module Number 1. Introduction to components of a computer system: Memory, 3 processor, I/O Devices, storage 2. Operating system –functions and services 10 3. Concept of assembler, compiler, interpreter, loader and linker 15 4. Idea of Algorithm: Representation of Algorithm, Flowchart, 17 Pseudo code with examples, From algorithms to programs, M1 source code. Introduction 5. Programming Basics: Structure of C program, Syntax , errors 22 6. Components of C language, Standard I/O in C, Fundamental 24 data types, Variables and memory locations 7. Storage classes 30 8. Arithmetic expressions and precedence: Operators and 34 expression using numeric and relational operators, mixed M2 operands, type conversion, logical operators, bit operations, (Arithmetic assignment operator, operator precedence and associability. expressions & 9. Conditional Branching: Applying if and switch statements, 43 Conditional nesting if and else, use of break and Default with switch. Branching) 10. Iteration and loops: use of while, do while and for loops, 47 M3 multiple loop variables, use of break and (Loops & 11. Functions- Introduction, types of functions, functions with array, 54 Functions) passing parameters to functions, Call by value, call by reference 12. Recursion 60 13. Arrays- Array notation and representation, manipulating array 63 elements, using multi dimensional arrays, passing arrays to functions M4 14. Basic Algorithms: Basic Sorting Algorithms (Bubble, Insertion 73 (Arrays & and Selection) Basic 15. Character arrays and strings 82 Algorithms) 16. Structure, Use of pointers in self-referential structures Structure 87 Array of structures 17. Union, enumeration 89 18. Notion of order of complexity 91 19. Pointers- Introduction, declaration, applications 93 M5 20. Introduction to dynamic memory allocation (malloc, calloc, 97 ( Pointer& File realloc, free) Handling) 21. Notion of linked list (no implementation) 101 22. File handling: File I/O functions 103 23. Standard C preprocessors, defining and calling macros, 106 command-line arguments Conditional compilation, passing values to the compiler 24. Important Programs with solution 113 25. Questions Bank 142 Downloaded from : uptukhabar.net DGI Greater Noida Module – 1: (Introduction to Programming) Topic: Introduction to components of a computer system: Memory, processor, I/O Devices, storage INTRODUCTION TO COMPUTERS Any programming language is implemented on a computer. Right from its inception, to the present day, all computer system (irrespective of their shape & size) perform the following 5 basic operations. It converts the raw input data into information, which is useful to the users. 1. Input: It is the process of entering data & instructions to the computer system. 2. Storing: The data & instructions are stored for either initial or additional processing, as & when required. 3. Processing: It requires performing arithmetic or logical operation on the saved data to convert itinto useful information. 4. Output: It is the process of producing the output data to the end user. 5. Controlling: The above operations have to be directed in a particular sequence to be completed. Based on these 5 operations, we can sketch the block diagram of a computer. Block Diagram of a Computer Input Unit: We need to first enter the data & instruction in the computer system, before any computation begins. This task is accomplished by the input devices. (The data accepted is in a human readable form. The input device converts it into a computer readable form. Input device: The input device is the means through which data and instructions enter in a computer. 1. Camera - most cameras like this are used during live conversations. The camera transmits a picture from one computer to another, or can be used to record a short video. Downloaded from : uptukhabar.net DGI Greater Noida 2. Compact Disc (CD) - CDs store information. The CD can then be put into another computer, and the information can be opened and added or used on the second computer. Note: A CD-R or CD-RW can also be used as an OUTPUT device. 3. Keyboard - The keyboard is a way to input letters or numbers into different applications or programs. A keyboard also has special keys that help operate the computer. 4. Mouse - The mouse is used to open and close files, navigate web sites, and click on a lot of commands (to tell the computer what to do) when using different applications. 5. Microphone - A microphone is used to record sound. The sound is then saved as a sound file on the computer. 6. Scanner - A scanner is used to copy pictures or other things and save them as files on the computer. 7. Joystick - A joystick is used to move the cursor from place to place, and to click on various items in programs. A joystick is used mostly for computer games. 8. Bar Code Scanner - A bar code scanner scans a little label that has a bar code on it. The information is then saved on the computer. Bar code scanners are used in libraries a lot. Storage Unit: The data & instruction that are entered have to be stored in the computer. Similarly, the end results & the intermediate results also have to be stored somewhere before being passed to the output unit. The storage unit provides solution to all these issues. This storage unit is designed to save the initial data, the intermediate result & the final result. This storage unit has 2 units: Primary storage & Secondary storage. Primary Storage: The primary storage, also called as the main memory, holds the data when the computer is currently on. As soon as the system is switched off or restarted, the information held in primary storage disappears (i.e. it is volatile in nature). Moreover, the primary storage normally has a limited storage capacity, because it is very expensive as it is made up of semiconductor devices. Downloaded from : uptukhabar.net DGI Greater Noida Secondary Storage: The secondary storage, also called as the auxiliary storage, handles the storage limitation & the volatile nature of the primary memory. It can retain information even when the system is off. It is basically used for holding the program instructions & data on which the computer is not working on currently, but needs to process them later. Magnetic Disk The Magnetic Disk is Flat, circular platter with metallic coating that is rotated beneath read/write heads. It is a Random access device; read/write head can be moved to any location on the platter. Floppy Disk These are small removable disks that are plastic coated with magnetic recording material. Floppy disks are typically 3.5″ in size (diameter) and can hold 1.44 MB of data. This portable storage device is a rewritable media and can be reused a number of times. Floppy disks are commonly used to move files between different computers. The main disadvantage of floppy disks is that they can be damaged easily and, therefore, are not very reliable. Hard disk. A hard disk consists of one or more rigid metal plates coated with a metal oxide material that allows data to be magnetically recorded on the surface of the platters. The hard disk platters spin at a high rate of speed, typically 5400 to 7200 revolutions per minute (RPM).Storage capacities of hard disks for personal computers range from 10 GB to 120 GB (one billion bytes are called a gigabyte). CD: Compact Disk (CD) is portable disk having data storage capacity between 650-700 MB. It can hold large amount of information such as music, full-motion videos, and text etc. It contains digital information that can be read, but cannot be rewritten. Separate drives exist for reading and writing Downloaded from : uptukhabar.net DGI Greater Noida CDs. Since it is a very reliable storage media, it is very often used as a medium for distributing large amount of information to large number of users. In fact today most of the software is distributed through CDs. DVD Digital Versatile Disk (DVD) is similar to a CD but has larger storage capacity and enormous clarity. Depending upon the disk type it can store several Gigabytes of data (as opposed to around 650MB of a CD). DVDs are primarily used to store music or movies and can be played back on your television or the computer too. They are not rewritable media. It‘s also termed DVD (Digital Video Disk) Memory Organization in Computer A memory unit is the collection of storage units or devices together. The memory unit stores the binary information in the form of bits. Generally, memory/storage is classified into 2 categories:  Volatile Memory: This loses its data, when power is switched off.  Non-Volatile Memory: This is a permanent storage and does not lose any data when power is switched off. Memory Hierarchy The total memory capacity of a computer can be visualized by hierarchy of components. The memory hierarchy system consists of all storage devices contained in a computer system from the slow Auxiliary Memory to fast Main Memory and to smaller Cache memory. Auxillary memory access time is generally 1000 times that of the main memory, hence it is at the bottom of the hierarchy. The main memory occupies the central position because it is equipped to communicate directly with the CPU and with auxiliary memory devices through Input/output processor (I/O). When the program not residing in main memory is needed by the CPU, they are brought in from auxiliary memory. Programs not currently needed in main memory are transferred into auxiliary memory to provide space in main memory for other programs that are currently in use. Downloaded from : uptukhabar.net DGI Greater Noida The cache memory is used to store program data which is currently being executed in the CPU. Approximate access time ratio between cache memory and main memory is about 1 to 7~10 Central Processing Unit: Together the Control Unit & the Arithmetic Logic Unit are called as the Central Processing Unit (CPU). The CPU is the brain of the computer. Like in humans, the major decisions are taken by the brain itself & other body parts function as directed by the brain. Similarly in a computer system, all the major calculations & comparisons are made inside the CPU. The CPU isresponsible for activating & controlling the operation of other units of the computer system. Arithmetic Logic Unit: The actual execution of the instructions (arithmetic or logical operations) takes place over here. The data & instructions stored in the primary storage are transferred as & when required. No processing is done in the primary storage. Intermediate results that are generated in ALU are temporarily transferred back to the primary storage, until needed later. Hence, data may move from the primary storage to ALU & back again to storage, many times, before the processing is done. Control Unit: This unit controls the operations of all parts of the computer but does not carry out any actual data processing.It is responsible for the transfer of data and instructions among other units of the computer.It manages and coordinates all the units of the system.It also communicates with Input/Output devices for transfer of data or results from the storage units. OutputUnit: The job of an output unit is just the opposite of an input unit. It accepts the results produced by the computer in coded form. It converts these coded results to human readable form. Finally, it displays the converted results to the outside world with the help of output devices ( Eg :monitors, printers, projectors etc..). Output device: Device that lets you see what the computer has accomplished. 1. Monitor - A monitor is the screen on which words, numbers, and graphics can be seem. The monitor is the most common output device. 2. Compact Disk - Some compact disks can be used to put information on. This is called burning information to a CD. NOTE: A CD can also be an input device. 3. Printer - A printer prints whatever is on the monitor onto paper. Printers can print words, numbers, or pictures. 4. Speaker - A speaker gives you sound output from your computer. Some speakers are built into the computer and some are separate. 5. Headphones - Headphones give sound output from the computer. They are similar to speakers, except they are worn on the ears so only one person can hear the output at a time. Downloaded from : uptukhabar.net DGI Greater Noida Hardware- This hardware is responsible for all the physical work of the computer. Software- This software commands the hardware what to do & how to do it. Together, the hardware & software form the computer system. This software is further classified as system software & application software. System Software- System software are a set of programs, responsible for running the computer, controlling various operations of computer systems and management of computer resources. They act as an interface between the hardware of the computer & the application software. E.g.: Operating System. Application software is a set of programs designed to solve a particular problem for users. It allows the end user to do something besides simply running the hardware. E.g.: Web Browser, Gaming Software, etc. Computer Classification: Computers can be generally classified by size and power as follows, though there is considerable overlap: a. Personal computer: a small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor fordisplaying information, and a storage device for saving data. b. Workstation: a powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor. c. Minicomputer: a multi-user computer capable of supporting from 10 to hundreds of users simultaneously. d. Mainframe: a powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. e. Supercomputer: an extremely fast computer that can perform hundreds of millions of instructions per second. Downloaded from : uptukhabar.net DGI Greater Noida For Reference Only **Digital Computer-A brief History Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices. First Generation (1940-1956) Vacuum Tubes  The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms.  They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.  First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve oneproblem at a time.  Input was based on punched cards and paper tape, and output was displayed on printouts.  The UNIVAC and ENIAC Computers are examples of first-generation computing devices. Second Generation (1956-1963) Transistors  Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors.  Second-generation computers still relied on punched cards for input and printouts for output.  Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN.  The first computers of this generation were developed for the atomic energy industry. Third Generation (1964-1971) Integrated Circuits  The development of the integrated circuit was the hallmark of the third generation of computers.  Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.  Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored thememory.  Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors. Fourth Generation (1971-Present) Microprocessors  The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.  The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.  As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet.  Fourth generation computers also saw the development of GUIs, the mouse and handheld devices. Fifth Generation (Present and Beyond) Artificial Intelligence  Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today.  The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Downloaded from : uptukhabar.net DGI Greater Noida Topic: Operating system –functions and services Notes Definition: An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. Definition:(1)As an interface (2) As an environment (3) As a system software Operating System functions: 1. Process Management 2.Main Memory management 3.I/O device management 4. File Management 5.Secondary storage management 6.Network Management 7. System Protection 8.Command interpretation Classification of operating systems: (i) Batch System: (a) Program, its related data and relevant control command should be submitted together, in the form of a job. (b) No interaction between the users and the executing programs, very simple, transfer control automatically. (c) Scheduling of jobs is in the order of FCFS (d) Memory management is done by Master/Slave concept. (e) No need of concurrency control. (f) Good for the programs which have long execution time. (ii) Interactive System: An operating system that allows users to run interactive programs. Pretty much all operating systems that are on PCs are interactive OS. (iii) Time Sharing System: 1. Time sharing (multitasking) is a logical extension of multiprogramming. The CPU executes multiple jobs by switching among them, but the switches occur so frequently that the users can interact with each program while it is running 2. CPU bound is divided into different time slots depending upon the number of users using the system. 3. There must be some CPU scheduling, memory management scheme, synchronization and communication schemes. (iv) Real Time System: 1. This type of operating systems are used to control Scientific devices and similar small instruments where memory and resources are crucial. These type of devices have very limited or no end user utilities , so more effort should go into making the OS really memory efficient and fast (less coding), so as to minimize the execution time ,in turn saving on power as well. E x: VHDL, 8086 etc. 2. Provide quick response time and thus to meet a scheduling deadline (time constraint).3. Resource utilization is secondary concern to these systems. 4. Applicable to Rocket launching, flight control, robotics.5. Types (a) soft RTS (b) hard RTS (v) Multiprocessor system: 1. Multiprocessor System consists of a set of processors that shares a set of physical memory blocks over an interconnection network. 2. Controls and manage the hardware and software resources such that user can view the entire system as a powerful uniprocessor system. Downloaded from : uptukhabar.net DGI Greater Noida 3. Design is too complex. 4. Parallel or tightly coupled systems. (vi) Multiuser System: 1. Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple users of a computer. 2. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving the CPU idle while it waits for I/O operations to complete. Common services provided by an operating system −  Program execution  I/O operations  File System manipulation  Communication  Error Detection  Resource Allocation  Protection **Additional Informations about OS- DOS (Disk Operating System) 1. Microsoft Disk operating system, MS-DOS is a non-graphical command line operating system derived from 86-DOS that was created for IBM compatible computers. MS-DOS originally written by Tim Paterson and introduced by Microsoft in August 1981 and was last updated in 1994. 2. Today, MS-DOS is no longer used; however, the command shell, more commonly known as the Windows command line is still used by many users. In the picture to the right, is an example of what a MS-DOS window more appropriately referred to as the Windows command line looks like under Microsoft Windows. 3. DOS (an acronym for Disk Operation System) is a tool which allows you to control the operation of the IBM PC. DOS is software which was written to control hardware. Essential DOS Commands and Concepts 1. Change the Default Drive To change the default drive, simply type the letter of the choice. The new default will be listed in subsequent DOS prompts. 2. CHDIR (CD) Change Directory Command Once you have located the directory you want, you may move from directory to directory using the CD command (change directory) 3. COPY Command The COPY command can be used both to copy files from disk to disk or to create a second copy of a file on a single disk. (There are many more uses of the COPY command, but only the basic operation is discussed here.) 4. DIR (Directory) Command The DIRECTORY command lists the names and sizes of all files located on a particular disk. 5. DIR Options Two little characters, '*' and '?', will make your life with computers much easier. Their use is illustrated below. 6. ERASE Command The ERASE command deletes specified files. Downloaded from : uptukhabar.net DGI Greater Noida 7. FORMAT Command You must format new disks before using them on the IBM computers. The format command checks a diskette for flaws and creates a directory where all the names of the diskette's files will be stored. 8. MKDIR (MD) Make Directory Command This command creates a new directory. 9. RENAME (REN) Command The RENAME command permits users to change the name of a file without making a copy of it. 10. RMDIR (RD) Remove Directory Command This command removes a directory. It is only possible to execute this command if the directory you wish to remove is empty. 11. Stop Execution (Ctrl-Break) If you wish to stop the computer in the midst of executing the current command, you may use the key sequence Ctrl-Break. Some other commands are: DATE, TIME, VER, CLS, and COPYCON. Microsoft Windows  Windows is a meta family of graphical operating systems developed, marketed, and sold by Microsoft.  Active Windows families include Windows NT, Windows Embedded and Windows Phone; these may encompass subfamilies, e.g. Windows Embedded Compact (Windows CE) or Windows Server. Defunct Windows families include Windows 9x; Windows 10 Mobile is an active product, unrelated to the defunct family Windows Mobile.  Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs).  Version history-Windows 1.0, Windows 2.0, and Windows 2.1xWindows 3.xWindows 9xWindows NT Windows XPWindows VistaWindows 7Windows 8 and 8.1Windows 10 Basic Features of Windows Operating System- 1) Windows Easy Transfer 2) Windows Anytime Upgrade3) Windows Basics 4) Searching and Organizing 5) Parental Controls 6) Ease of Access Center 7) Default Programs 8) Remote Desktop Connection Linux  The Unix operating system was conceived and implemented in 1969 at AT&T's Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna.  Linux Operating System has primarily three components  Kernel − Kernel is the core part of Linux. It is responsible for all major activities of this operating system. It consists of various modules and it interacts directly with the underlying hardware. Kernel provides the required abstraction to hide low level hardware details to system or application programs.  System Library − System libraries are special functions or programs using which application programs or system utilities accesses Kernel's features. These libraries implement most of the functionalities of the operating system and do not requires kernel module's code access rights.  System Utility − System Utility programs are responsible to do specialized, individual level tasks. Downloaded from : uptukhabar.net DGI Greater Noida Basic Features Following are some of the important features of Linux Operating System.  Portable − Portability means software can works on different types of hardware in same way. Linux kernel and application programs supports their installation on any kind of hardware platform.  Open Source − Linux source code is freely available and it is community based development project. Multiple teams work in collaboration to enhance the capability of Linux operating system and it is continuously evolving.  Multi-User − Linux is a multiuser system means multiple users can access system resources like memory/ ram/ application programs at same time.  Multiprogramming − Linux is a multiprogramming system means multiple applications can run at same time.  Hierarchical File System − Linux provides a standard file structure in which system files/ user files are arranged.  Shell − Linux provides a special interpreter program which can be used to execute commands of the operating system. It can be used to do various types of operations, call application programs. etc.  Security − Linux provides user security using authentication features like password protection/ controlled access to specific files/ encryption of data. Architecture The architecture of a Linux System consists of the following layers −  Hardware layer − Hardware consists of all peripheral devices (RAM/ HDD/ CPU etc).  Kernel − It is the core component of Operating System, interacts directly with hardware, provides low level services to upper layer components.  Shell − An interface to kernel, hiding complexity of kernel's functions from users. The shell takes commands from the user and executes kernel's functions.  Utilities − Utility programs that provide the user most of the functionalities of an operating systems. Android What is Android-One of the most widely used mobile OS these days is ANDROID. Android is a software bunch comprising not only operating system but also middleware and key applications. Android Inc was founded in Palo Alto of California, U.S. by Andy Rubin, Rich miner, Nick sears and Chris White in 2003. Later Android Inc. was acquired by Google in 2005. After original release there have been number of updates in the original version of Android Downloaded from : uptukhabar.net DGI Greater Noida  Features & Specifications Android is a powerful Operating System supporting a large number of applications in Smart Phones. These applications make life more comfortable and advanced for the users. Android applications are written in java programming language. Android is available as open source for developers to develop applications which can be further used for selling in android market. For software development, Android provides Android SDK (Software development kit). Applications These are the basics of Android applications: Android applications are composed of one or more application components (activities, services, content providers, and broadcast receivers) Each component performs a different role in the overall application behavior, and each one can be activated individually (even by other applications) The manifest file must declare all components in the application and should also declare all application requirements, such as the minimum version of Android required and any hardware configurations required Non-code application resources (images, strings, layout files, etc.) should include alternatives for different device configurations (such as different strings for different languages) Downloaded from : uptukhabar.net DGI Greater Noida Topic: Concept of assembler, compiler, interpreter, loader and linker  A language that is acceptable to a computer system is called a computer language or programming language and the process of creating a sequence of instructions in such a language is called programming or coding.  A program is a set of instructions, written to perform a specific task by the computer. A set of large program is called software. To develop software, one must have knowledge of a programming language.  Before moving on to any programming language, it is important to know about the various types of languages used by the computer. COMPUTER LANGUAGES  Languages are a means of communication. Normally people interact with each other through a language. On the same pattern, communication with computers is carried out through a language. This language is understood both by the user and the machine.  Just as every language like English, Hindi has its own grammatical rules; every computer language is also bounded by rules known as syntax of that language. The user is bound by that syntax while communicating with the computer system. Computer languages are broadly classified as:  Low Level Language: The term low level highlights the fact that it is closer to a language which the machine understands The low level languages are classified as:  Machine Language: This is the language (in the form of 0‘s and 1‘s, called binary numbers) understood directly by the computer. It is machine dependent. It is difficult to learn and even more difficult to write programs.  Assembly Language: This is the language where the machine codes comprising of 0‘sand 1‘s are substituted by symbolic codes (called mnemonics) to improve their understanding. It is the first step to improve programming structure. Assembly language programming is simpler and less time consuming than machine level programming, it is easier to locate and correct errors in assembly language than in machine language programs. It is also machine dependent. Programmers must have knowledge of the machine on which the program will run.  High Level Language: Low level language requires extensive knowledge of the hardware since it is machine dependent. To overcome this limitation, high level language has been evolved which uses normal English, which is easy to understand to solve any problem. High level languages are computer independent and programming becomes quite easy and simple. Various high level languages are given below:  BASIC (Beginners All Purpose Symbolic Instruction Code): It is widely used, easy to learn general purpose language. Mainly used in microcomputers in earlier days.  COBOL (Common Business Oriented language): A standardized language used for commercial applications.  FORTRAN (Formula Translation): Developed for solving mathematical and scientific problems. One of the most popular languages among scientific community.  C: Structured Programming Language used for all purpose such as scientific application, commercial application, developing games etc. Downloaded from : uptukhabar.net DGI Greater Noida  C++: Popular object oriented programming language, used for general purpose. PROGRAMMING LANGUAGE TRANSLATORS  As you know that high level language is machine independent and assembly language though it is machine dependent yet mnemonics that are being used to represent instructions are not directly understandable by the machine. Hence to make the machine understand the instructions provided by both the languages, programming language instructors are used.  They transform the instruction prepared by programmers into a form which can be interpreted & executed by the computer. Flowing are the various tools to achieve this purpose: Compiler: The software that reads a program written in high level language and translates it into an equivalent program in machine language is called as compiler. The program written by the programmer in high level language is called source program and the program generated by the compiler after translation is called as object program. Interpreter: it also executes instructions written in a high level language. Both complier & interpreter have the same goal i.e. to convert high level language into binary instructions, but their method of execution is different. The complier converts the entire source code into machine level program, while the interpreter takes 1 statement, translates it, executes it & then again takes the next statement. Assembler: The software that reads a program written in assembly language and translates it into an equivalent program in machine language is called as assembler. Linker: A linker or link editor is a computer program that takes one or more object files generated by a compiler and combines them into a single executable file, library file, or another object file. Downloaded from : uptukhabar.net DGI Greater Noida Topic: Idea of Algorithm: Representation of Algorithm, Flowchart, Pseudo code with examples, From algorithms to programs, source code. Algorithm  Characteristics of algorithm: Input, output, definiteness, finiteness, effectiveness.  Algorithm is a step-by-step solution to a problem. Example: one algorithm for adding two digit numbers is "add the units, add the tens and combine the answers"  "Algorithm" is named after the 9th century Persian mathematician Al-Khwarizmi. Example: For factorial 1. Start 2. Input number N (for which we want to calculate factorial.) 3. Let M=1 and F=1. 4. F=F*M. 5. Is M=N? 6. If NO then M=M+1 and go to step 3. 7. If YES then output F 8. End Flow Chart: A flowchart is a type of diagram that represents an algorithm or process, showing the steps as boxes of various kinds, and their order by connecting these with arrows. This diagrammatic representation can give a step-by-step solution to a given problem. Example: For factorial. Advantages Of Using FLOWCHARTS: -  Communication: - Flowcharts are better way of communicating the logic of a system to all concerned.  Effective analysis: - With the help of flowchart, problem can be analyzed in more effective way. Downloaded from : uptukhabar.net DGI Greater Noida  Proper documentation: - Program flowcharts serve as a good program documentation, which is needed for various purposes.  Efficient Program Maintenance: - The maintenance of operating program becomes easy with the help of flowchart. It helps the programmer to put efforts more efficiently on that part Disadvantages Of Using FLOWCHARTS: - 1. Complex logic: - Sometimes, the program logic is quite complicated. In that case, flowchart becomes complex and clumsy. 2. Alterations and Modifications: - If alterations are required the flowchart may require re- drawing completely. 3. Reproduction: - As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem. 4. The essentials of what is done can easily be lost in the technical details of how it is done. Examples of Algorithm and Flowchart (Random)-For hint 1. Draw flowchart to find the largest among three different numbers entered by user. Downloaded from : uptukhabar.net DGI Greater Noida 2.Draw a flowchart to find all the roots of a quadratic equation ax2+bx+c=0 3.Draw a flowchart to find the Fibonacci series till term≤1000. Example : Calculate the Interest of a Bank Deposit Algorithm:  Step 1: Read amount,  Step 2: Read years,  Step 3: Read rate,  Step 4: Calculate the interest with formula "Interest=Amount*Years*Rate/100  Step 5: Print interest, Downloaded from : uptukhabar.net DGI Greater Noida Flowchart: Example : Determine and Output Whether Number N is Even or Odd Algorithm:  Step 1: Read number N,  Step 2: Set remainder as N modulo 2,  Step 3: If remainder is equal to 0 then number N is even, else number N is odd,  Step 4: Print output. Flowchart: Downloaded from : uptukhabar.net DGI Greater Noida Example : Determine Whether A Student Passed the Exam or Not: Algorithm:  Step 1: Input grades of 4 courses M1, M2, M3 and M4,  Step 2: Calculate the average grade with formula "Grade=(M1+M2+M3+M4)/4"  Step 3: If the average grade is less than 60, print "FAIL", else print "PASS". Flowchart: Downloaded from : uptukhabar.net DGI Greater Noida Topic: Programming Basics: Structure of C program, Syntax , errors STRUCTURE OF A C PROGRAM The structure of a C program is a protocol (rules) to the programmer, which he has to follow while writing a C program. The general basic structure of C program is shown in the figure below. Based on this structure, we can sketch a C program. Example: #include void main(void) { int number; printf( "Please enter a number: " ); scanf( "%d", &number ); printf( "You entered %d", number ); return 0; } Stepwise explanation: #include The part of the compiler which actually gets your program from the source file is called the preprocessor. #include #include is a pre-processor directive. It is not really part of our program, but instead it is an instruction to the compiler to make it do something. It tells the C compiler to include the contents of a file (in this case the system file called stdio.h). The compiler knows it is a system file, and therefore must be looked for in a special place, by the fact that the filename is enclosed in characters stdio.h is the name of the standard library definition file for all Standard Input and Output functions. Your program will almost certainly want to send information to the screen and read things from the keyboard, and stdio.h is the name of the file in which the functions that we want to use are defined. The function we want to use is called printf. The actual code of printf will be tied in later by the linker. The ".h" portion of the filename is the language extension, which denotes an include file. void This literally means that this means nothing. In this case, it is referring to the function whose name follows.Void tells to C compiler that a given entity has no meaning, and produces no error. Main In this particular example, the only function in the program is called main. A C program is typically made up of large number of functions. Each of these is given a name by the programmer and they refer to each other as the program runs.C regards the name main as a special case and will Downloaded from : uptukhabar.net DGI Greater Noida run this function first i.e. the program execution starts from main. A parameter to a function gives the function something to work on. { (Brace) This is a brace (or curly bracket). As the name implies, braces come in packs of two - for every open brace there must be a matching close one. Braces allow us to group pieces of program together, often called a block. A block can contain the declaration of variable used within it, followed by a sequence of program statements. In this case the braces enclose the working parts of the function main. ;( semicolon) The semicolon marks the end of the list of variable names, and also the end of that declaration statement. All statements in C programs are separated by ";" (semicolon) characters. The ";" character is actually very important. It tells the compiler where a given statement ends. If the compiler does not find one of these characters where it expects to see one, then it will produce an error. scanf In other programming languages, the printing and reading functions are a part of the language. In C this is not the case; instead they are defined as standard functions which are part of the language specification, but are not a part of the language itself. The standard input/output library contains a number of functions for formatted data transfer; the two we are going to use are scanf (scan formatted) and printf (print formatted). printf The printf function is the opposite of scanf. It takes text and values from within the program and sends it out onto the screen. Just like scanf, it is common to all versions of C and just like scanf, it is described in the system file stdio.h.The first parameter to a printf is the format string, which contains text, value descriptions and formatting instructions. FILES USED IN A C PROGRAM Source File- This file contains the source code of the program. The file extension of any c file is.c. The file contains C source code that defines the main function & maybe other functions. Header File- A header file is a file with extension.h which contains the C function declarations and macro definitions and to be shared between several source files. Object File- An object file is a file containing object code, with an extension.o, meaning relocatable format machine code that is usually not directly executable. Object files are produced by an assembler, compiler, or other language translator, and used as input to the linker, which in turn typically generates an executable or library by combining parts of object files. Executable File- The binary executable file is generated by the linker. The linker links the various object files to produce a binary file that can be directly executed. Types of error a) Syntax Errors: Errors in syntax (grammar) of the program. b) Semantic Errors: Errors in the meaning of the program. c) Logical Errors: Errors in logic of the program. Compiler cannot diagnose these kinds of errors. d) Runtime Errors: i) Insufficient memory ii)Floating exception e) Compile Errors: i) parse error ii)implicit declaration iii) no matching function iv)Unsatisfied symbols v)incomplete type vi)cannot call member function vii)bad argument viii)cannot allocate an object Downloaded from : uptukhabar.net DGI Greater Noida ,j m Special Character !@#$%^&* White space Tab or new lines or space Keywords Keywords are the words whose meaning has already been explained to the C compiler. The keywords cannot be used as variable names because if we do so we are trying to assign a new meaning to the keyword, which is not allowed by the computer. There are only 32 keywords available in C. Below figure gives a list of these keywords for your ready reference. Identifier In the programming language C, an identifier is a combination of alphanumeric characters, the first being a letter of the alphabet or an underline, and the remaining being any letter of the alphabet, any numeric digit, or the underline. Two rules must be kept in mind when naming identifiers. 1. The case of alphabetic characters is significant. Using "INDEX" for a variable is not the same as using "index" and neither of them is the same as using "InDeX" for a variable. All three refer to different variables. 2. As C is defined, up to 32 significant characters can be used and will be considered significant by most compilers. If more than 32 are used, they will be ignored by the compiler. Downloaded from : uptukhabar.net DGI Greater Noida Data Type In the C programming language, data types refer to a domain of allowed values & the operations that can be performed on those values. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted. There are 4 fundamental data types in C, which are- char, int, float &, double. Char is used to store any single character; int is used to store any integer value, float is used to store any single precision floating point number & double is used to store any double precision floating point number. We can use 2 qualifiers with these basic types to get more types. There are 2 types of qualifiers- Sign qualifier- signed & unsigned Size qualifier- short & long The data types in C can be classified as follows: Type Storage size Value range Char 1 byte -128 to 127 unsigned char 1 byte 0 to 255 Integrity 2 or 4 bytes 32,768 to 32,767 or -2,147,483,648 to 2,147,483,647 nsigned integrity 2 or 4 bytes 0 to 65,535 or 0 to 4,294,967,295 Short 2 bytes -32,768 to 32,767 unsigned short 2 bytes 0 to 65,535 long 4 bytes -2,147,483,648 to 2,147,483,64 unsigned long 4 bytes 0 to 4,294,967,295 Type Storage size Value range Precision float 4 bytes 1.2E-38 to 3.4E+38 6 decimal places double 8 bytes 2.3E-308 to 1.7E+308 15 decimal places long double 10 bytes.4E-4932 to 1.1E+4932 19 decimal places Downloaded from : uptukhabar.net DGI Greater Noida Constants A constant is an entity that doesn‘t change whereas a variable is an entity that may change constants can be divided into two major categories: Primary Constants, Secondary Constants Rules for Constructing Integer Constants:  An integer constant must have at least one digit.  It must not have a decimal point.  It can be either positive or negative.  If no sign precedes an integer constant it is assumed to be positive.  No commas or blanks are allowed within an integer constant  The allowable range for integer constants is -32768to 32767. Ex.: 426, +782,-8000, -7605 Rules for Constructing Real Constants:  Real constants are often called Floating Point constants. The real constants could be written in two forms—Fractional form and Exponential form.  A real constant must have at least one digit.  It must have a decimal point.  It could be either positive or negative.  Default sign is positive.  No commas or blanks are allowed within a real constant. Ex. +325.34, 426.0, -32.76, - 48.5792 Rules for constructing real constants expressed in exponential form:  The mantissa part and the exponential part should be separated by a letter e.  The mantissa part may have a positive or negative sign.  Default sign of mantissa part is positive. Downloaded from : uptukhabar.net DGI Greater Noida  The exponent must have at least one digit, which must be a positive or negative integer. Default sign is positive.  Range of real constants expressed in exponential form is -3.4e38 to 3.4e38.  Ex. +3.2e-5, 4.1e8, -0.2e+3, -3.2e-5 Rules for Constructing Character Constants: A character constant is a single alphabet, a single digit or a single special symbol enclosed within single inverted commas. The maximum length of a character constant can be 1 character. Ex.: ‗M‘, ‗6‘, ‗+‘ VARIABLES Variables are names that are used to store values. It can take different values but one at a time. A data type is associated with each variable & it decides what values the variable can take. Variable declaration requires that you inform C of the variable's name and data type. Syntax – data type variable name; Eg:int page_no; char grade; float salary; long y; Declaring Variables: There are two places where you can declare a variable: After the opening brace of a block of code (usually at the top of a function) Before a function name (such as before main() in the program) Consider various examples: Initialization of Variables When a variable is declared, it contains undefined value commonly known as garbage value. If we want we can assign some initial value to the variables during the declaration itself. This is called initialization of the variable. Eg-int pageno=10; Expressions An expression consists of a combination of operators, operands, variables & function calls. An expression can be arithmetic, logical or relational. Here are some expressions: a+b – arithmetic operation a>b- relational operation a == b - logical operation func (a,b) – function call Statements Statements are the primary building blocks of a program. A program is a series of statements with some necessary punctuation. A statement is a complete instruction to the computer. In C, statements are indicated by a semicolon at the end. a semicolon is needed to identify instructions that truly are statements. INPUT-OUTPUT IN C When we are saying Input that means we feed some data into program. This can be given in the form of file or from command line. C programming language provides a set of built-in functions to read given input and feed it to the program as per requirement. Downloaded from : uptukhabar.net DGI Greater Noida When we are saying Output that means to display some data on screen, printer or in any file. C programming language provides a set of built-in functions to output the data on the computer screen. Functions printf() and scanf() are the most commonly used to display out and take input respectively. Let us consider an example: #include //This is needed to run printf() function. int main() { printf("C Programming"); //displays the content inside quotation return 0; } Output:C Programming Explanation: Every program starts from main() function. printf() is a library function to display output which only works if #includeis included at the beginning. Here, stdio.h is a header file (standard input output header file) and #include is command to paste the code from the header file when necessary. When compiler encounters printf()function and doesn't find stdio.h header file, compiler shows error. return 0; indicates the successful execution of the program. Input- Output of integers in C #include int main() {int c=5; printf("Number=%d",c); return 0; } Output:Number=5 Input - Output of characters #include int main() {char var1; printf("Enter character: "); scanf("%c",&var1); printf("You entered %c.",var1); return 0; } Output:Enter character: g You entered g. FORMATTED INPUT-OUTPUT Data can be entered & displayed in a particular format. Through format specifications, better presentation of results can be obtained. Variations in Output for integer & floats: #include int main() {printf("Case 1:%6d\n",9876); printf("Case 2:%3d\n",9876); Downloaded from : uptukhabar.net DGI Greater Noida printf("Case 3:%.2f\n",987.6543); printf("Case 4:%.f\n",987.6543); printf("Case 5:%e\n",987.6543); return 0; } Output Case 1: 9876 Case 2:9876 Case 3:987.65 Case 4:988 Downloaded from : uptukhabar.net DGI Greater Noida Topic: Storage classes  Generally there are two kinds of locations in a computer where such a value can be present, these are Memory and CPU registers. The storage class of a particular variable determines in which of the above two locations the variable‘s value is stored.  There are four properties by which storage class of a variable can be recognized. These are scope, default initial value, scope and life.  A variable‘s storage class reveals the following things about a variable (i) Where the variable is stored. (ii) What is the initial value of the variable if the value of the variable is not specified? (iii) What is the scope of the variable (To which function or block the variable is available). (iv) What is the life of particular variable (Up to what extent the variable exists in a program).  In c there are four types of storage class. They are: 1. Auto 2. Register 3. Static 4. Extern  Storage class is modifier or qualifier of data types which decides: In which area of memory a particular variable will be stored? What is scope of variable? What is visibility of variable? Visibility of a variable in c: Visibility means accessibility. Up to witch part or area of a program, we can access a variable, that area or part is known as visibility of that variable. For example: In the following figure yellow color represents visibility of variable a. Scope of a variable in c: Meaning of scope is to check either variable is alive or dead. Alive means data of a variable has not destroyed from memory. Up to which part or area of the program a variable is alive, that area or part is known as scope of a variable. There are four type of scope in c: 1. Block scope. 2. Function scope. 3. File scope. 3. Program scope. Automatic Storage Class Syntax to declare automatic variable is: auto datatype variablename; Example: auto int i; Features of Automatic Storage Class are as follows Storage: Memory Default Initial Value: Garbage Value Downloaded from : uptukhabar.net DGI Greater Noida Scope: Local to the block in which the variable is defined Life: Till the control remains within the block in which the variable is defined by default every variable is automatic variable The following program illustrates the work of automatic variables. void test(); void main() { test(); test(); test(); } void test() { auto int k=10; printf(―%d\n‖,k); k++; } Output: 10 10 10 In the above program when the function test() is called for the first time ,variable k is created and initialized to 10. When the control returns to main(), k is destroyed. When function test() is called for the second time again k is created , initialized and destroyed after execution of the function. Hence automatic variables came into existence each time the function is executed and destroyed when execution of the function completes. Register Storage Class Syntax to declare register variable is: register datatype variablename; Features of Register Storage Class are as follows: Storage: CPU Registers Default Initial Value: Garbage Value Scope: Local to the block in which the variable is defined Life: Till the control remains within the block in which the variable is defined For example loop counters are declared as register variables, which are defined as follows: int main() { register int a; for(a=0;i Checks if the value of left operand is greater than the value (A > B) is not of right operand, if yes then condition becomes true. true. < Checks if the value of left operand is less than the value of (A < B) is true. right operand, if yes then condition becomes true. >= Checks if the value of left operand is greater than or equal to (A >= B) is not the value of right operand, if yes then condition becomes true. true. > 2 will give 15 value is moved right by the number of bits specified which is 0000 1111 by the right operand. Downloaded from : uptukhabar.net DGI Greater Noida Assignment Operators: In C programs, values for the variables are assigned using assignment operators. There are following assignment operators supported by C language: Operator Description Example = mple assignment operator, Assigns values from right side C = A + B will operands to left side operand assign value of A + B into C += d AND assignment operator, It adds right operand to the C += A is left operand and assign the result to left operand equivalent to C = C +A -= Subtract AND assignment operator, It subtracts right C -= A is operand from the left operand and assign the result to left equivalent to C = C Operand –A *= Multiply AND assignment operator, It multiplies right C *= A is operand with the left operand and assign the result to left equivalent to C = C Operand *A /= Divide AND assignment operator, It divides left operand C /= A is ith the right operand and assign the result to left operand equivalent to C = C /A %= odulus AND assignment operator, It takes modulus using C %= A is two operands and assign the result to left operand equivalent to C = C %A > 2 &= Bitwise AND assignment operator C &= 2 is same as C=C&2 ^= bitwise exclusive OR and assignment operator C ^= 2 is same as C =C^2 |= bitwise inclusive OR and assignment operator C |= 2 is same as C =C|2 Downloaded from : uptukhabar.net DGI Greater Noida Increment/Decrement OPERATOR In C, ++ and – are called increment and decrement operators respectively. Both of these operators are unary operators, i.e, used on single operand. ++ adds 1 to operand and – subtracts 1 to operand respectively. For example: Let a=5 and b=10 a++; //a becomes 6 a--; //a becomes 5 ++a; //a becomes 6 --a; //a becomes 5 When i++ is used as prefix(like: ++var), ++var will increment the value of var and then return it but, if ++ is used as postfix(like: var++), operator will return the value of operand first and then only increment it. This can be demonstrated by an example: #include int main() {int c=2,d=2; printf(―%d\n‖,c++); //this statement displays 2 then, only c incremented by 1 to 3. Printf(―%d‖,++c); //this statement increments 1 to c then, only c is displayed. Return 0; } Output:2 4 Conditional Operators (? :) Conditional operators are used in decision making in C programming, i.e, executes different statements according to test condition whether it is either true or false. Syntax of conditional operators; conditional_expression?expression1:expression2 If the test condition is true (that is, if its value is non-zero), expression1 is returned and if false expression2 is returned. y = ( x> 5 ? 3 : 4 ) ;this statement will store 3 in y if x is greater than 5, otherwise it will store 4 in y. Misc Operators: There are few other operators supported by c language. Operator Description Example sizeof() It is a unary operator which is used in sizeof(a), where a is integer, will finding the size of data type, constant, return 4. arrays, structure etc. & Returns the address of a variable. &a; will give actual address of the variable. * Pointer to a variable. *a; will pointer to a variable. Downloaded from : uptukhabar.net DGI Greater Noida Operators Precedence in C Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator. For example x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3*2 and then adds into 7. Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first. Category Operator Associativity Postfix () [] ->. ++ - - Left to right Unary + - ! ~ ++ - - (type)* &sizeof Right to left Multiplicative */% Left to right Additive +- Left to right Shift Left to right Relational = Left to right Equality == != Left to right Bitwise AND & Left to right Bitwise XOR ^ Left to right Bitwise OR | Left to right Logical AND && Left to right Logical OR || Left to right Conditional ?: Right to left Assignment = += -= *= /= %=>>=