Chapter 1. Introduction to Computers and Programming

23 slides
0.06 MB
725 views

Similar Presentations

Presentation Transcript

1

Chapter 1. Introduction to Computers and Programming

2

1.1 Why Program?Computers can do many different jobs because they are programmable.

3

1.2 Computer Systems: Hardware and SoftwareAll computer systems consist of similar hardware devices and software components. This section provides an overview of standard computer hardware and software organization.

4

HardwareThe CPU Main Memory Secondary Storage Input Devices Output Devices

5

Figure 1.1Input DeviceCentral Processing UnitMain MemoryOutput DeviceOutput Device

6

Figure 1.2Arithmetic and Logic Unit Control UnitInstruction (Input)Result (Output)

7

SoftwareOperating Systems Single tasking Multi-tasking Application Software

8

1.3 Programs and Programming LanguagesWhat is a program? A set of instructions a computer follows in order to perform a task. A programming language is a special language used to write computer programs.

9

Program 1-1// This program calculates the user’s pay. #include void main(void) { float hours, rate, pay; cout << “How many hours did you work? ”; cin >> hours; cout << “How much do you get paid per hour? ”; cin >> rate; pay = hours * rate; cout << “You have earned $” << pay << endl; }

10

Program OutputHow many hours did you work? 10 How much do you get paid per hour? 15 You have earned $150

11

Programming LanguagesFigure 1-4High level (Close to Human Language)Low level (Machine Language)

12

Table 1-1

13

1.4 What is a Program Made of?There are certain elements that are common to all programming languages. Key Words Programmer-Defined Symbols Operators Punctuation

14

Language Elements, Table 1-2

15

Lines and Statementscout << “How many hours did you work?”;

16

VariablesA storage location in the computer’s memory for holding a piece of information. Symbolic names that represent locations in the computer’s random-access memory.

17

Variable DeclarationsTwo types of information: numbers and characters Numbers may be integers or floating-point numbers The statement below creates three variables in memory named hours, rate, and pay that each can store a floating point number float hours, rate, pay;

18

1.5 Input, Processing, and OutputInput: cin >> hours; Processing: pay = hours * rate; Output cout<<“You have earned $”<

19

1.6 The Programming ProcessThe programming process consists of several steps, which include design, creation, testing and debugging activities.

20

Designing and Creating a Program1. Clearly define what the program is to do 2. Visualize the program running on the computer. 3. Design a flowchart or hierarchy chart 4. Check the flowchart or hierarchy chart for logical errors.

21

5. Write a pseudocode version of the program. 6. Check the pseudocode for errors. 7. Write the actual program on paper. 8. Desk-check the program for errors. 9. Enter the code and compile it. 10. Correct any errors found during compilation. Repeat steps 9 and 10 as many times as necessary.

22

11. Run the program with test data for input. Correct any errors found while running the program. Repeat steps 9 through 12 as many times as necessary. Validate the results of the program.

23

1.7 Procedural and Object-Oriented ProgrammingProcedural programming and object-oriented programming are two ways of thinking about software development and program design.

Browse More Presentations

Last Updated: 8th March 2018

Recommended PPTs