Computer Programming 1 Module 1 PDF

1 Introduction A computer is a machine that performs a variety of tasks according to specific instructions. It is a programmable electronic device, which accepts data or information via an input device, and its processor manipulates the information at high speed according to a program. The comput...

1 Introduction A computer is a machine that performs a variety of tasks according to specific instructions. It is a programmable electronic device, which accepts data or information via an input device, and its processor manipulates the information at high speed according to a program. The computer has two major components. Hardware, which is the tangible part of the computer. It is composed of electronic and mechanical parts. Software, which is the intangible part of a computer. It consists of data and the computer programs. Basic Components of a Computer 1. Hardware The Central Processing Unit The processor is the “brain” of the computer. It contains millions of extremely tiny electrical parts. It does the fundamental computing within the system. Examples of processors are Pentium, Athlon and SPARC. Memory The memory is where data and instructions needed by the CPU to do its appointed tasks can be found. It is divided into several storage locations that have corresponding addresses. The CPU accesses the memory with the use of these addresses. 1. Main Memory The main memory is very closely connected to the processor. It is used to hold programs and data, that the processor is actively working with. It is not used for long- term storage. It is sometimes called the RAM (Random Access Memory). The computer's main memory is considered as volatile storage. This means that once the computer is turned off, all information residing in the main memory is erased. 2. The Secondary Memory The secondary memory is connected to main memory. It is used to hold programs and data for long term use. Examples of secondary memory are hard disks and cd/dvd drives, USB flash drives 1st Semester, A.Y. 2023-2024  2 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Secondary memory is considered as non-volatile storage. This means that information residing in secondary memory is not erased after the computer is turned off. Main Secondary Property Memory Memory Fast Slow Speed Expensive Cheap Price Low High Capacity Yes No Volatile Table 1: Comparison between main memory and secondary memory Input and Output Devices Input and output devices allow a computer system to interact with the outside world by moving data into and out of the system. Examples of input devices are keyboard, mouse, microphone Examples of output devices are monitor, printer and speaker Software Software is the program that a computer uses in order to function. It is kept on some hardware device like a hard disk, but it itself is intangible. The data that the computer uses can be anything that a program needs. A Program acts like instructions for the processor. Some Types of Computer Programs: 1. Systems Programs Programs that are needed to keep all the hardware and software systems running together smoothly Examples: Operating Systems like Linux, Windows, Unix, Solaris, MacOSx 2. Application Programs Programs that people use to get their work done Examples: Word Processor MODULE 1  3 Game Apps Compilers / IDEs 3. Utility Programs These are used to enhance the performance of the Computer System. Examples: Disk Defragmenter Disk Repair Network Managers Overview of Computer Programming Languages What is a Programming Language? A programming language is a standardized communication technique for expressing instructions to a computer. Like human languages, each language has its own syntax and grammar. Programming languages enable a programmer to precisely specify what data a computer will act upon, how these data will be stored/transmitted, and precisely what actions to take under various circumstances. There are different types of programming languages that can be used to create programs, but regardless of what language you use, these instructions are translated into machine language that can be understood by computers. Kinds of Computer Programming Languages 1. Machine Language also called machine code, low-level language , in binary form which a particular computer can execute directly. 2. Assembly Language is a low-level programming language. Assembly language is converted into machine code executable with the help of an assembler program. 3. High Level Languages are machine independent. Design to be used by human or 1st Semester, A.Y. 2023-2024  4 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies the programmer. Programming style and context is easier to learn and implement. C/C++ and Java are examples. 4. System Language is used for system programming, designed to write system software and low level tasks, like memory and process management. Nim, Rust, Go, C/C++ are the best examples. 5. Scripting Language is an extremely high level and powerful language. Used to write scripts containing series of commands, which are interpreted one at a time at runtime. Scripting is generally used to make dynamic web applications. 6. Visual Languages allow the user to create illustrations to describe various processes, manipulating graphical elements rather than typing textual commands. Alice, Lego Mindstorms, Scratch are few examples. Programming Paradigms A programming paradigm is the style or way of programming. A program can feature multiple paradigms. These are the known programming paradigms; Imperative: Approach with an explicit sequence of commands that update state. Declarative: Done with specifying the result you want, not how to get it. Structured: Programming with clean, goto-free, nested control structures. Procedural: Is an Imperative programming with procedure calls. Functional (Applicative): Using function calls that avoid any global state. Function-Level (Combinator): Uses no variables at all. Object-Oriented: Defines objects that send messages to each other. Objects have their own internal (encapsulated) state and public interfaces. Object orientation can be: Class-based and Prototype-based. Event-Driven: Programming with emitters and listeners of asynchronous actions. Flow-Driven: Programming processes communicating with each other over predefined channels. Logic (Rule-based): Specifies a set of facts and rules. An engine infers the answers to questions. Constraint: Specifies a set of constraints. An engine finds the values that meet the constraints. Aspect-Oriented: Programming cross-cutting concerns applied transparently. Reflective: Programming by manipulating the program elements themselves. Array: Programming with powerful array operators that usually make loops unnecessary. MODULE 1  5 The Program Development Life Cycle Programmers do not sit down and start writing code right away when trying to make a computer program. Instead, they follow an organized plan or methodology, that breaks the process into a series of tasks. Here are the basic steps in trying to solve a problem on the computer: 1. Problem Definition 2. Problem Analysis 3. Algorithm design and representation (Pseudocode or flowchart) 4. Coding and debugging In order to understand the basic steps in solving a problem on a computer, let us define a single problem that we will solve step-by-step as we discuss the problem solving methodologies in detail. The problem we will solve will be defined in the next section. Problem Definition A programmer is usually given a task in the form of a problem. Before a program can be designed to solve a particular problem, the problem must be well and clearly defined first in terms of its input and output requirements. A clearly defined problem is already half the solution. Computer programming requires us to define the problem first before we even try to create a solution. Let us now define our example problem: “Create a program that will determine the number of times a name occurs in a list.” Problem Analysis After the problem has been adequately defined, the simplest and yet the most efficient and effective approach to solve the problem must be formulated. Usually, this step involves breaking up the problem into smaller and simpler sub-problems. Example Problem: Determine the number of times a name occurs in a list Input to the program: list of names, name to look for Output of the program: the number of times the name occurs in a list 1st Semester, A.Y. 2023-2024  6 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Algorithm Design and Representation Once the problem is clearly defined, set to finding a solution. In computer programming, it is normally required to express a solution in a step-by-step manner. An Algorithm is a clear and unambiguous specification of the steps needed to solve a problem. It may be expressed in either Human language (English, Tagalog), through a graphical representation like a flowchart or through a pseudocode, which is a cross between human language and a programming language. Now given the problem defined in the previous sections, how do we express our general solution in such a way that it is simple yet understandable? Expressing our solution through Human language: 1. Get the list of names 2. Get the name to look for, let's call this the keyname 3. Compare the keyname to each of the names in the list 4. If the keyname is the same with a name in the list, add 1 to the count 5. If all the names have been compared, output the result Expressing our solution through a flowchart Figure 2: Example of a Flowchart Expressing our solution through pseudocode: Let nameList = List of Names Let keyName = the name to be sought Let Count = 0 For each name in NameList do the following if name == keyName Count = Count + 1 Display Count Figure 2: Example of a Pseudocode Flowcharting Symbols and Description A flowchart is a design tool used to graphically represent the logic in a solution. Flowcharts typically do not display programming language commands. Rather, they state the concept in English or mathematical notation. MODULE 1  7 Here are some the commonly used symbols in creating flowcharts. Table 2: Flowchart Symbols Symbol Name Meaning Represents the process of executing a defined operation or groups of operations that results in a change in value, form, or Process Symbol location of information. Also functions as the default symbol when no other symbol is available. Represents an I/O function, which makes data available for processing (input) or Input/Output displaying (output)of processed information. (I/O) Symbol Represents the sequence of available information and executable operations.The lines connect other symbols, and the Flowline Symbol arrowheads are mandatory only for right-to- left and bottom-to-top flow. Represents the addition of descriptive information, comments, or explanatory Annotation notes as clarification. The vertical line and Symbol the broken line may be placed on the left, as shown, or on the right. Represents a decision that determines which of a number of alternative paths is to be Decision Symbol followed. Represents the beginning, the end, or a point of interruption or delay in a program. Terminal Symbol Represents any entry from, or exit to, Connector another part of the flowchart. Also serves as Symbol an off-page connector. Represents a named process consisting of one or more operations or program steps Predefined that are specified elsewhere. Process Symbol Coding and Debugging After constructing the algorithm, it is now possible to create the source code. Using the algorithm as basis, the source code can now be written using the chosen programming language. 1st Semester, A.Y. 2023-2024  8 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Most of the time, after the programmer has written the program, the program is not 100% working right away. The programmer has to add some fixes to the program in case of errors (also called bugs) that occurs in the program. This process of is called debugging. There are two types of errors that a programmer will encounter along the way. The first one is compile-time error, and the other is runtime error. Compile-Time Errors occur if there is a syntax error in the code. The compiler will detect the error and the program won't even compile. At this point, the programmer is unable to form an executable that a user can run until the error is fixed. Forgetting a semi-colon at the end of a statement or misspelling a certain command, for example, is a compile-time error. It's something the compiler can detect as an error. Compilers are not perfect and so cannot catch all errors at compile time. This is especially true for logic errors such as infinite loops. This type of error is called runtime error. For example, the actual syntax of the code looks okay. But when you follow the code's logic, the same piece of code keeps executing over and over again infinitely so that it loops. In such a case, compilers aren't really smart enough to catch all of these types of errors at compile-time, and therefore, the program compiles fine into an executable file. However, and unfortunately, when the end-user runs the program, the program (or even their whole computer) freezes up due to an infinite loop. Other types of run-time errors are when an incorrect value is computed, the wrong thing happens, etc. Number Systems and Conversion Numbers can be represented in a variety of ways. The representation depends on what is called the BASE. The following are the four most common representations. Decimal We normally represent numbers in their decimal form. Numbers in decimal form are in base 10. This means that the only digits that appear are 0-9. Here are examples of numbers written in decimal form: 12610 (normally written as just 126) 1110 (normally written as just 11) Binary Numbers in binary form are in base 2. This means that the only legal digits are 0 and 1. We need to write the subscript 2 to indicate that the number is a binary number. Here are examples of numbers written in binary form: 11111102 10112 MODULE 1  9 Octal Numbers in octal form are in base 8. This means that the only legal digits are 0-7. We need to write the subscript 8 to indicate that the number is an octal number. Here are examples of numbers written in octal form: 1768 138 Hexadecimal Numbers in hexadecimal form are in base 16. This means that the only legal digits are 0-9 and the letters A-F (or a-f, lowercase or uppercase does not matter). We need to write the subscript 16 to indicate that the number is a hexadecimal number. Here are examples of numbers written in hexadecimal form: 7E16 B16 Hexadecimal 0 1 2 3 4 5 6 7 8 9 A B C D E F Decimal Equivalent 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Table 3: Hexadecimal Numbers and their Equivalence to decimal numbers Decimal Binary Octal Hexadecimal 12610 11111102 1768 7E16 1110 10112 138 B16 Table 4: Summary of Examples Conversion Process Decimal to Binary / Binary to Decimal To convert a decimal number to binary, continuously divide the number by 2 and get the remainder (which is either 0 or 1), and get that number as a digit of the binary form of the number. Get the quotient and divide that number again by 2 and repeat the whole process until the quotient reaches 0 or 1. We then get all the remainders starting from the last remainder, and the result is the binary form of the number. NOTE: The last digit is already less than the divisor (which is 2) just copy the value to the remainder portion. For Example: 12610 = ? 2 Quotient Remainder 126 / 2 = 63 0 63 / 2 = 31 1 Write 31 / 2 = 15 1 it this 15 / 2 = 7 1 way 7 / 2 = 3 1 3 / 2 = 1 1 1 / 2 = 1 So, writing the remainders from the bottom up, we get the binary number 11111102 To convert a binary number to decimal, we multiply the binary digit to "2 raised to the position of the binary number". We then add all the products to get the resulting decimal number. 1st Semester, A.Y. 2023-2024  10 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies For Example: 11111102 = ? 10 Position 6 5 4 3 2 1 0 Binary 1 1 1 1 1 1 0 Digits 0 x 20 = 0 1 x 21 = 2 1 x 22 = 4 1 x 23= 8 1 x 24= 16 1 x 25 = 32 1 x 26 = 64 TOTAL: 126 Decimal to Octal (or Hexadecimal)/Octal (or Hexadecimal) to Decimal Converting decimal numbers to Octal or hexadecimal is basically the same as converting decimal to binary. However, instead of having 2 as the divisor, you replace it with 8(for octal) or 16 (for hexadecimal). For Example (Octal): 12610 = ? 8 Quotient Remainder Write it 126 / 8 = 15 6 this 15 / 8 = 1 7 way 1/8= 1 So, writing the remainders from the bottom up, we get the octal number 1768 For Example (Hexadecimal): 12610 = ? 16 Quotient Remainder Write 14 (equal to hex digit E) it 126 / 16 = 7 this 7 / 16 = 7 way Writing the remainders from the bottom up, we get the hexadecimal number 7E16 Converting octal or hexadecimal numbers is also the same as converting binary numbers to decimal. To do that, we will just replace the base number 2 with 8 for Octal and 16 for hexadecimal. MODULE 1  11 For Example (Octal): 1768 = ? 10 Position 2 1 0 Octal Digits 1 7 6 6 x 80 = 6 7 x 81 = 56 1 x 82 = 64 TOTAL: 126 For Example (Hexadecimal): 7E16 = ? 10 Position 1 0 Hex Digits 7 E 14 x 160 = 14 7 x 161 = 112 TOTAL: 126 Binary to Octal / Octal to Binary To convert from binary numbers to octal, we partition the binary number into groups of 3 digits (from right to left), and pad it with zeros if the number of digits is not divisible by 3. We then convert each partition into its corresponding octal digit. The following is a table showing the binary representation of each octal digit. Octal Digit Binary Representation 0 000 1 001 2 010 3 011 4 100 5 101 6 110 7 111 Table 5: Octal Digits and their corresponding binary represenation For Example: 11111102 = ? 8 0 0 1 1 1 1 1 1 0 1st Semester, A.Y. 2023-2024  12 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies 0 0 1 1 1 1 1 1 0 1 7 6 Equivalent octal number Converting octal numbers to binary is just the opposite of what is given above. Simply convert each octal digit into its binary representation (given the table) and concatenate them. The result is the binary representation. Binary to Hexadecimal / Hexadecimal to Binary To convert from binary numbers to hexadecimal, we partition the binary number into groups of 4 digits (from right to left), and pad it with zeros if the number of digits is not divisible by 4. We then convert each partition into its corresponding hexadecimal digit. The following is a table showing the binary representation of each hexadecimal digit. Hexadecimal Binary Digit Representation 0 0000 1 0001 2 0010 3 0011 4 0100 5 0101 6 0110 7 0111 8 1000 9 1001 A 1010 B 1011 C 1100 D 1101 E 1110 F 1111 Table 6: Hexadecimal Digits and their corresponding Binary Representation MODULE 1  13 For Example: 11111102 = ? 16 0 1 1 1 1 1 1 0 E 7 Equivalent Hexadecimal Number Converting hexadecimal numbers to binary is just the opposite of what is given above. Simply convert each hexadecimal digit into its binary representation (given the table) and concatenate them. The result is the binary representation. FLOWCHART EXAMPLES: Example 1 Create a flowchart that will count from 1 to 10. Start Ctr = 0 B Ctr=Ctr+1 No Is Ctr = B 10 Yes End Example 2 Draw a simple flowchart to show the counting process of an integer 1 - 10 and add the numbers. 1st Semester, A.Y. 2023-2024  14 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Example 3. Create a Flowchart that will print the sum and average of the given grade Q1:35, Q2:50, Q3:60, Q4:35. Example 4: Given three numbers A, B and C. Draw a flowchart to compute and print out the sum, the average, and the product of these values. A:5 ; B:8 ; C:10. MODULE 1  15 ACTIVITY 1 Name:_________________ Score/Rating:______________ Course:_______________ Date: ____________________ Writing Algorithms Given the following tasks, be able to write the algorithm, pseudo-code and draw the flowchart of each. 1. Bake a Bread 2. Borrow a book in the library 3. Compute the average of three numbers. 4. Calculate and output the volume of a box with a length of 73 cm, width is 47 cm, and height is 29 cm. 5. Write an algorithm to print the tree below: * *** ***** ******* 6. Write an algorithm to read two numbers that represent the length of two sides of a right triangle; compute and print the length of its hypotenuse. 7. Write an algorithm (and draw a flowchart) that reads three numbers, calculate and print the sum and average. 8. Write an algorithm (and draw a flowchart) of the enrollment process in Gordon College. 9. Write an algorithm for taking a bath. 10. Write an algorithm for cooking your favorite dish. 1st Semester, A.Y. 2023-2024  16 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies ACTIVITY 2 Name:_________________ Score/Rating:______________ Course:________________ Date: ____________________ Number System Conversion Convert the following and show complete solution/process: 1. 198510 to binary, hexadecimal and octal 2. 11011011012 to decimal, hexadecimal and octal 3. 778 to binary, hexadecimal and decimal 4. 45F16 to binary, decimal and octal 5. BEBE16 to binary, decimal and octal MODULE 1  17 BRIEF HISTORY OF C LANGUAGE The C programming language was developed at Bell Labs during the early 1970's. Derived from a computer language named B and from an earlier language BCPL. Initially designed as a system programming language under UNIX it expanded to have wide usage on many different systems. The earlier versions of C became know as K&R C after the authors of an earlier book, "The C Programming Language" by Kernighan and Ritchie. As the language further developed and standardized, a version known as ANSI (American National Standards Institute) C became dominant. As you study this language expect to see references to both K&R and ANSI C. Although it is no longer the language of choice for most new development, it still is used for some system and network programming as well as for embedded systems. More importantly, there is still a tremendous amount of legacy software still coded in this language and this software is still actively maintained. WHY C? C is a small language. It does not have many keywords and its standard libraries are not too big, yet it is very powerful. C is the native language of the UNIX operating system - a major operating system on large machines. It is usually the first high-level language available on any new computer, including microcomputers, minicomputers, and mainframes. It allows the programmer a wide range of operations from high level down to a very low level, approaching the level of assembly language. C is the standard development language for personal computers. Many PC packages such as database programs, graphics libraries etc. are written in C. C language supports structured and modular programming. C programs are generally quite portable. The C syntax is a base for many other programming languages, such as C++, Java, PERL and PHP. The last two are the languages used to write programs on Web servers. 1st Semester, A.Y. 2023-2024  18 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Structure of C Language Program 1. Comment Line - It indicates the purpose of the program. It is represented as. Comment line is used for increasing the readability of the program and is use in explaining the program and generally used for documentation. Comment line can be single or multiple-line but should not be nested. It can be anywhere in the program except inside string constant and character constant. 2. Preprocessor Directive - #include tells the compiler to include information about the standard input/output library. It is also used in symbolic constant such as #define PI 3.14(value). The stdio.h (standard input output header file) contains definition and declaration of system defined function such as printf( ), scanf( ), pow( ) etc. Generally printf() function used to display and scanf() function used to read value. 3. Global Variable Declaration -This is the section where variable are declared globally so that it can be accessed by all the functions used in the program. And it is generally declared outside the function. 4. Main ( ) Function - Every function has one main() function from where actually program is started and is enclosed within the pair of curly braces. The main( ) function can be anywhere in the program but in general practice it is placed in the first position. Syntax : The main function does not return any value main() when void (means null/empty) as; {........................ } void main(void ) or void main() The main( ) function returns value when it { declared by data type as; printf (“C language”); int main( ) } { return 0 } Output: C language The program execution starts with opening braces and end with closing brace. And in between the two braces declaration part as well as executable part is mentioned. And at the end of each line, the semi- colon is given which indicates statement termination. { Local variables; Statements; } User defined function } } #include int main (void) { printf ("Welcome to C Programming Language.\n"); return 0; } MODULE 1  19 Output: Welcome to C Programming Language. Steps for Compiling and Executing A Program A compiler is a software program that analyzes a program developed in a particular computer language and then translates it into a form that is suitable for execution on a particular computer system. Figure 1. shows the steps that are involved in entering, compiling, and executing a computer program developed in the C programming language. Step 1: The program that is to be compiled is first typed into a file on the computer system using an Editor or an IDE. There are various conventions that are used for naming files, typically be any name provided the last two characters are “.c” or file with extension.c. So, the file name prog1.c is a valid filename for a C program. An editor is usually used to enter the C program into a file. The program that is entered into the file is known as the source program because it represents the original form of the program expressed in the C language. Step 2: After the source program has been entered into a file, then proceed to have it compiled. The compilation process is initiated by typing a special command on the system. In the first step of the compilation process, the compiler examines each program statement contained in the source program and checks it to ensure that it conforms to the syntax and semantics of the language. If the compiler discovers mistakes during this phase, they are reported to the user and the compilation process ends right there. The errors then have to be corrected in the source program (with the use of an editor), and the compilation process must be restarted. Typical errors reported during this phase of compilation might be due to an expression that has unbalanced parentheses (syntactic error), or due to the use of a variable that is not “defined” (semantic error). Step 3: When all the syntactic and semantic errors have been removed from the program, the compiler then proceeds to take each statement of the program and translate it into a “lower” form that is equivalent to assembly language program needed to perform the identical task. Step 4: After the program has been translated, the next step in the compilation process is to translate the assembly language statements into actual machine instructions. The assembler takes each assembly language statement and converts it into a binary format known as object code, which is then written into another file on the system. This file has the same name as the source file, with the file extension “o” (for object) instead of a “c”. Step 5: After the program has been translated into object code, it is ready to be linked. This process is once again performed automatically using the IDE. The purpose of the linking phase is to get the program into a final form for execution on the computer. If the program uses other programs that were previously processed by the compiler, then during this phase the programs are linked together. Programs that are used from the system’s program library are also searched and linked together with the object program during this phase. The process of compiling and linking a program is often called building. The final linked file, which is in an executable object code format, is stored in another file on the system, ready to be run or executed. Under Windows, the executable file usually has the same name as the source file, with the c extension replaced by an.exe extension. Step 6: When the program is executed, each of the statements of the program is sequentially executed in turn. If the program requests any data from the user, known as input, the program temporarily suspends its execution so that the input can be entered. Or, the program might simply wait for an event, such as a mouse being clicked, to occur. Results that are displayed by the program, known as output, appear in a window, sometimes called the console. If the program does not produce the desired results, it is necessary to go back and reanalyze the program’s logic. This is known as the debugging phase, during which an attempt is made to remove all the known problems or bugs from 1st Semester, A.Y. 2023-2024  20 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies the program. To do this, it will most likely be necessary to make changes to original source program. Figure 1. The Process of Writing a C Program Source: https://www3.ntu.edu.sg/home/ehchua/programming/cpp/images/C_DevelopmentProcesses.png Figure 2. Program Compilation and Execution Why Learn C Programming? C is everywhere. Almost every computer operating system is written in C, including smartphones and other handheld devices. Most microcontrollers is programmed in C. C++, Objective C, and C# all are built directly on top of C, and Python was written in it. A good knowledge of C will add points on MODULE 1  21 programmer’s resume. Programming Tips for First Time C Programmers 1. Learn the Basic Variable Types 2. Learn the Operators 3. Learn and Use the C Standard Libraries 4. Know that C is unforgiving. 5. Debugging is your bestfriend. It is essential to know what type of data you are working with. It is a must to know that the number 5 may be used as an integer or a character type in a program. Data types and how they are assigned to variables is an essential part of every programming course. C uses many operators for arithmetic, assignment, relational and logic among others. Using libraries in your C source code is an essential programming practice. Just like in any other programming language, Garbage In Garbage Out, C will do what you tell it, and instead of complaining when something does not make sense even when the program executes, you might end up with some weird bugs. C will not help you find what is wrong. To stop yourself from losing your mind, get comfortable with debugging your codes. Integrated Development Environment (IDE) and Compiler for C Programmers Integrated Development Environment or IDE is an application or software which programmers use for programming. It helps a programmer to program easily by providing all comprehensive facilities required for the development of software. It can improve the productivity of a programmer or developer because of its fast setup and various tools. An IDE includes three (3) parts, source code editor; build automation tool (compiler) and a debugger. The source code editor is where programmers write the codes, build automation tool is used by the programmers for compiling the codes and the debugger is used to test or debug the program in order to resolve any errors in the code. IDEs also comes with features like object and data modeling, unit testing, source code library, and a lot more. Here are some of the IDEs and Compilers for C. 1. Visual Studio Code - One of the most popular in according to a survey done by Stack Overflow. It is an open-source code editor developed by Microsoft for Windows, Linux and Mac OS. Visual Studio Code is based on an Electron framework. 2. Eclipse - Powerful and useful IDE used by developers for C/C++ programming. It is an open-source software which is simple and easy to use. Originally, it was used for Java Programming but now it is used for various languages. Eclipse can run Windows, Linux and Mac OS. 3. Code::Blocks – It is a free, open-source IDE developed in C++. An extensible and highly customizable IDE that performs on all platforms including Linux, Mac and Windows. Any function can be added to this IDE by installing or coding a plugin. 4. Dev-C++ - It is a full-featured IDE for C or C++ languages. Uses MinGW port of GNU Compiler Collection (GCC) or any other GCC compilers. 5. Borland Turbo C - Turbo C is an IDE and compiler for the C programming language from Borland. First introduced in 1987, it was noted for its small size, fast compile speed, comprehensive manuals and low price. ***NOTE: Discussion in this module and program codes are written/run using this compiler. 6. CppDroid – Simple C/C++ IDE and compiler for android devices. It is focused on learning programming languages and libraries. This app is freely available. 7. Mobile C – A mobile application that supports C programming. This does not require internet connection to run your codes. ***NOTE: You may use this App on your mobile phone to write/run source codes in this module. A good alternative for learners without PC/Laptop. 1st Semester, A.Y. 2023-2024  22 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies 8. Online C compilers - There are various C Compilers that are available online. These are good alternatives for devices with limited resources (device storage and processors) but requires internet connection. Online Compilers are embedded on websites that provides online tutorials. The Borland Turbo C Compiler Environment Basic Parts of the Turbo C IDE Figure 2. Turbo C Basic Interface The edit window is where you type your program. The cursor moves while you type your program statements and its positions in line and column are shown at the bottom of the edit window. The close box of a window is the box in the upper left corner. Click this box to quickly close the window. (Or choose Window | Close.) The title bar, the topmost horizontal bar of a window, contains the name of the window and the window number. Double-clicking the title bar zooms the window. You can also drag the title bar to move the window around. The zoom box appears in the upper right corner of the window. In the above screen, the window is in regular size. Click it to zoom the window to the maximum size. Click it again to return the window back to the normal size. The Sub Menu MODULE 1  23 How to Compile and Run a C Program Locate the TC.exe file and open it. Click File>New and then write your C Program as shown below. #include int main() { printf("hello World!"); return 0; } SOURCES: https://cs.lmu.edu/~ray/notes/pltypes/ Save the program by pressing F2 on your keyboard or File Menu > Save, remember the file extension must be “.C”. The screenshot below shows a filename as helloworld.C. 1st Semester, A.Y. 2023-2024  24 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Compile the program using ALT+F9 or Compile>Compile as shown below. Press Ctrl+F9 using your keyboard to RUN or Select Run>Run using the menu bar. To view the output of the program at the output screen, press ALT+F5. Dissecting the C Program The C program starts with #include. This line includes the "standard I/O library" into the program. The standard I/O library lets you read input from the keyboard (called "standard in"), write output to the screen (called "standard out"), process text files stored on the disk, and so on. It is an extremely useful library. C has a large number of standard libraries like stdio, including string, time and math libraries. A library is simply a package of code that someone else has written to make your life easier (will be discussed bit later). The line int main() declares the main function. Every C program must have a function named main somewhere in the code. You will learn more about functions shortly. At run time, program execution starts at the first line of the main function. In C, the { and } symbols mark the beginning and end of a block of code. In this case, the block of code making up the main function contains two lines. MODULE 1  25 The printf statement in C allows you to send output to standard out (in this example, the screen). The portion in quotes is called the format string and describes how the data is to be formatted when printed. The format string can contain string literals such as "hello World! \n " symbols for carriage returns (\n), and operators as placeholders for variables. The return 0; line causes the function to return an error code of 0 (no error) to the shell that started execution. The Character Set, Identifiers A character denotes any alphabet, digit or special symbol used to represent information. The alphabets, numbers and special symbols when properly combined form constants, variables and keywords. The figure below shows alphabets, numbers and special symbols which are characters allowed in C. Figure 3. C Valid Character Set C Identifiers Identifiers are user-defined words used to name entities like variables, arrays, functions, structures and the like. These are the rules for naming identifiers; 1. Names should only consist of alphabets (can be upper and lower case), digits and underscore (_) symbol. 2. The first character should be an alphabet or an underscore. 3. Names should not be a keyword in C. 4. C is case sensitive, the upper case and lower case are considered differently. HELLO, hello, Hello are different identifiers. 5. Identifiers must be used in meaningful, descriptive manner. Use names to denote meaning and description of entities such as value, net_salary, age, data etc. ANSI standard compiler can recognize identifiers with 31 characters. Here are some invalid identifiers; 5cb, int, res#, avg no Keyword C Language has certain words reserved for doing specific tasks, these words are known as reserved word or keywords. These are predefined which are written in lower case. Keywords cannot be used as variable names, since they represent special meaning in the C Language. Some examples are int, short, signed, unsigned, default, volatile, float, long, double, break, continue, typedef, static, do, for, union, return, while, do, extern, register, enum, case, goto, struct, char, auto, const etc. Figure 4. C Keywords and Reserved Words 1st Semester, A.Y. 2023-2024  26 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Data Types Data type is a classification that specifies the type of value a variable can hold. Used for declaring variables or functions of different types before its use. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted. There are four (4) classifications of data types in C; Basic Built-In (int, float, double, char) Derived (pointer, array, structure, union), Void(void), Enumeration(enum). C Basic Data Types The C primary or fundamental types are the Integer, Floating Point and the Char Types. The Integer types are further classified as the table shows. Table 7. Classification of the Integer Data Type When a variable declared is of type int, this can contain integral values only, values that do not contain decimal places. A variable declared to be of type float can be used for storing floating- point numbers (values containing decimal places). The double type is the same as type float, with twice the precision. The char data type can be used to store a single character, such as the letter a, the digit character 6, or a symbol. A variable declared as char can only store character type value. A type qualifier ( size – short/long or sign – signed/unsigned) can be used together with the specified variable data type. The sign qualifier unsigned is used when the number is always positive, and when signed is used, number may be positive or negative. If not mentioned, then by default signed qualifier is assumed. The range of values for signed data types is less than that of unsigned data type. Because in signed type, the left most bit is used to represent sign, while in unsigned type this bit is also used to represent the value. The table below shows the size and range of the different data types on a 16-bit machine. Table 8. Data Types Size and Range MODULE 1  27 Constants A Constant is any value that cannot be changed during program execution. It is an entity that does not change whereas a variable is an entity that may change. For example, a number 10 represents a constant integer value. The character string "I love Programming in C.\n" is an example of a constant character string. C constants can be divided into two major categories: Primary Constants and Secondary Constants, and further categorized as the figure below shows. Figure 5. Categories of Constants Variables Variable is a name used in a program to reference a location where a data or value is stored in memory or storage. The value of the variable can be change during the execution. The rule for naming variables is the same as naming identifiers. Before a variable is used in a program, it must be declared first. Variable declaration specifies its name and data type. The range of the value that can be stored in a variable depends on its data type. Variable Declaration Example : int a; char c; float f; Data Types Used : int, char, float Variable Names : a, c, f When a variable is assigned an initial value during the declaration, it is called initialization of variable. A variable is initialized with the assignment operator such as; Data type variable name=constant; Example: int a=20; Or int a; a=20; Expressions An expression is a program statement that evaluates to a certain value. It is combination of variables, constants, operators and function call. Expressions can be arithmetic, logical and relational. Example: int a= c+d is an arithmetic expression c>b is a relational expression d==b is a logical expression func(x, z) is a function call Operators A symbol used to perform some operations on variables, operands or with a constant. Operators may require two (2) operands (binary) to perform an operation or may require single operand (unary). Figure 6. Types of Operators 1st Semester, A.Y. 2023-2024  28 [COMPUTER PROGRAMMING 1 MODULE] BY : ARMILYN T. MARTINEZ, MSIT Gordon College- College of Computer Studies Operator Precedence, Associativity and Assignment Operator Precedence dictates the order of evaluation of operators in an expression while associativity defines the order in which operators of the same precedence are evaluated in an expression. Associativity can be either from left to right or right to left. Table 8. Operator Precedence and Associativity Source: overIQ.com Examples: ANS : -8 MODULE 1  29 ACTIVITY 3 Name:_________________ Score/Rating:______________ Course:________________ Date: ____________________ A. Using the C Compiler / IDE, Compile , Debug and Run the program to get the Output as shown below. Note: Make sure to identify and correct the errors in the program to get the expected program output. Program: #include int main() { int a, b, c; a = 7; b = 5; c=a+b printf("%d %d = %d\n, a, b, c); return 0; } EXPECTED PROGRAM OUTPUT: 7 + 5 = 12 B. Answer the following questions. 1. List down the steps you made to create, through getting the output of the program above. 2. List down the steps to save a C source file. 3. How did you debug the program? List down the steps. 4. Why do you need to debug a program? 5. List down problems/challenges/issues you encountered during the process and write down the solutions/process you performed to solve the issues/problems. C. What are the Types of Operators? List down and discuss, include sample expressions in your discussion. D. Compute for the final value of x. Show step by step solution. x = (1+4-2)*3^2-1%1/(1-(1+3*1)) 1st Semester, A.Y. 2023-2024