Chapter 1: Introduction to Computers and Programming PDF

Chapter 1: Introduction to Computers and Programming © Pearson Education Limited 2015 Programme Outcome Graduates with broad based knowledge and fundamentals of engineering to solve problems, generate new ideas and develop products for the need of the society...

Chapter 1: Introduction to Computers and Programming © Pearson Education Limited 2015 Programme Outcome Graduates with broad based knowledge and fundamentals of engineering to solve problems, generate new ideas and develop products for the need of the society Graduates with competencies in Engineering design and analysis. Successful and productive engineers with skill in communication, management, teamwork and leadership. Graduates with good understanding of moral values, professional ethics and responsibility towards society and environment Graduates who recognize the importance of and engage in life- long learning. The OBE model is a student-centered learning philosophy which focuses on measuring the students’ performance instead of the lecturers © Pearson Education Limited 2015 1.1 Why Program? Concept : computers can do many different jobs because they are programmable Computer – programmable machine designed to follow instructions Program – instructions in computer memory to make it do something Programmer – person who writes instructions (programs) to make computer perform a task SO, without programmers, no programs; without programs, a computer cannot do anything © Pearson Education Limited 2015 1.2 Computer System: Hardware and Software Hardware : Refers to physical components that a computer is made of. Computer is not an individually device, but a system of devices Main Hardware Component 1. Central Processing Unit (CPU) 2. Main Memory 3. Secondary Memory / Storage 4. Input Devices 5. Output Devices © Pearson Education Limited 2015 Main Hardware Component Categories © Pearson Education Limited 2015 Input Devices Devices that send information to the computer from outside Many devices can provide input: Keyboard, mouse, scanner, digital camera, microphone Disk drives, CD drives, and DVD drives Output Devices Output is any information the computers sends to the outside world. This information is sent to output device, which formats and present it. Monitors, printers, speakers © Pearson Education Limited 2015 Central Processing Unit (CPU) When a computer is performing the tasks that a program tells it to do, we say that the computer is running or executing the program. → CPU is the part of the computer that actually runs the program. → w/o CPU, computer cannot run software The CPU’s job is to fetch the instructions, follow the instructions and produce some result. Internally, it consists of: the control unit and the arithmetic and logic unit (ALU) © Pearson Education Limited 2015  CPU Organization Design and perform the mathematical operations Coordinates all the computer’s operations Determine where to get A cycle when a computer is running a program: the next instruction Fetch → Decode → Execute © Pearson Education Limited 2015 Main Memory Also called Random Access Memory (RAM) It is volatile. Main memory is erased when program terminates or computer is turned off → Temporary storage while the program is running. → When the program is terminated, the content of RAM are erased. Organized as follows: bit: smallest piece of memory. Has values 0 (off, false) or 1 (on, true) → bits stand for binary digits byte: 8 consecutive bits. Each Byte is assigned a unit number known as addresses. © Pearson Education Limited 2015 Main Memory In Figure, the number 149 is stored in the byte with the address 16, and the number 72 is stored at address 23. © Pearson Education Limited 2015 Secondary Storage Non-volatile: data retained when program is not running or computer is turned off Comes in a variety of media: magnetic: floppy disk, hard drive optical: CD-ROM, DVD Flash drives, connected to the USB port © Pearson Education Limited 2015 Software Categories of software: System software: programs that manage the computer hardware and the programs that run on them. Examples: operating systems, utility programs, software development tools Application software: programs that provide services to the user. Examples : word processing, games, programs to solve specific problems © Pearson Education Limited 2015 1.3 Program and Programming Languages A program is a set of instructions that the computer follows to perform a task We start with an algorithm, which is a set of well-defined steps. © Pearson Education Limited 2015 Program and Programming Languages Types of languages: Low-level: used for communication with computer hardware directly. Often written in binary machine code (0’s/1’s) directly. High-level: closer to human language © Pearson Education Limited 2015 Machine Language The computer only executes machine language instructions. Machine language instructions are binary numbers, such as 1011010000000101 Rather than writing programs in machine language, programmers use programming languages. © Pearson Education Limited 2015 Some Well-known Programming Languages C++ BASIC Ruby FORTRAN Java Visual Basic COBOL C# JavaScript C Python © Pearson Education Limited 2015  From a High-Level Program to an Executable File a) Create file containing the program with a text editor. b) Run preprocessor to convert source file directives to source code program statements. c) Run compiler to convert source program into machine instructions. d) Run linker to connect hardware-specific code to machine instructions, producing an executable file. Steps b–d are often performed by a single command or button click. Errors detected at any step will prevent execution of following steps. © Pearson Education Limited 2015 From a High-Level Program to an Executable File © Pearson Education Limited 2015 Integrated Development Environments (IDEs) An integrated development environment, or IDE, combine all the tools needed to write, compile, and debug a program into a single software application. Examples are Microsoft Visual C++, Turbo C++ Explorer, CodeWarrior, etc. © Pearson Education Limited 2015 Integrated Development Environments (IDEs) © Pearson Education Limited 2015 1.4 What is a Program Made of? Common elements in programming languages: Key Words Programmer-Defined Identifiers Operators Punctuation Syntax © Pearson Education Limited 2015 Program 1-1 © Pearson Education Limited 2015 Program 1-1 © Pearson Education Limited 2015 Key Words © Pearson Education Limited 2015 Key Words Also known as reserved words Have a special meaning in C++ Can not be used for any other purpose Key words in the Program 1-1: using, namespace, int, double, and return © Pearson Education Limited 2015 Programmer-Defined Identifiers © Pearson Education Limited 2015 Programmer-Defined Identifiers Names made up by the programmer Not part of the C++ language Used to represent various things: variables (memory locations), functions, etc. In Program 1-1: hours, rate, and pay. © Pearson Education Limited 2015 Operators © Pearson Education Limited 2015 Operators Used to perform operations on data Many types of operators: Arithmetic - ex: +,-,*,/ Assignment – ex: = Some operators in Program1-1: > = * © Pearson Education Limited 2015 Punctuations © Pearson Education Limited 2015 Punctuations Characters that mark the end of a statement, or that separate items in a list In Program 1-1: , and ; © Pearson Education Limited 2015 Syntax The rules of grammar that must be followed when writing a program Controls the use of key words, operators, programmer-defined symbols, and punctuation © Pearson Education Limited 2015 Variables A variable is a named storage location in the computer’s memory for holding a piece of data. In Program 1-1 we used three variables: The hours variable was used to hold the hours worked The rate variable was used to hold the pay rate The pay variable was used to hold the gross pay © Pearson Education Limited 2015 Variables Definition To create a variable in a program you must write a variable definition (also called a variable declaration) Here is the statement from Program 1-1 that defines the variables: double hours, rate, pay; © Pearson Education Limited 2015 Variables Definition There are many different types of data, which you will learn about in this course. A variable holds a specific type of data. The variable definition specifies the type of data a variable can hold, and the variable name. © Pearson Education Limited 2015 Variables Definition Once again, line 7 from Program 1-1: double hours, rate, pay; The word double specifies that the variables can hold double-precision floating point numbers. (You will learn more about that in Chapter 2) © Pearson Education Limited 2015 Examples of visualized program © Pearson Education Limited 2015 1.5 Input, Processing and Output Three steps that a program typically performs: 1) Gather input data: from keyboard from files on disk drives 2) Process the input data 3) Display the results as output: send it to the screen write to a file © Pearson Education Limited 2015 1.7 Procedural and Object-Oriented Programming Procedural programming: focus is on the process. Procedures/functions are written to process data. Object-Oriented programming: focus is on objects, which contain data and the means to manipulate the data. Messages sent to objects to perform operations. © Pearson Education Limited 2015