1. C++ Programming: From Problem Analysis to Program Design
Chapter 1: An Overview of Computers and Programming Languages
Dr .Hanaa.M

2. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

3. Objectives In this chapter you will:
Learn about different types of computers
Explore the hardware and software components of a computer system
Learn about the language of a computer
Examine high-level programming languages

4. Objectives (continued)
Discover what a compiler is and what it does
Examine a C++ Program and explore how a C++ program is processed
Become aware of Standard C++ and ANSI/ISO Standard C++

5. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

6. Categories of Computers
Mainframe computers
Midsize computers
Micro computers (personal computers)

7. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

8. Elements of a Computer System
Hardware
Central Processing Unit (CPU)
Main Memory
Secondary Storage
Input/ Output Devices
Software

9. Central Processing Unit (CPU)
The main components of the CPU are:
Control unit (CU)
Arithmetic and logic unit (ALU).
Registers.

10. Central Processing Unit (CPU)
CU (Control Unit):
Fetches and decodes instructions
Controls flow of information in and out of MM
Controls operation of internal CPU components
ALU (arithmetic logic unit): carries out all arithmetic and logical operations

11. Central Processing Unit (CPU)
3. Registers.
PC (program counter): points to next instruction to be executed
IR (instruction register): holds instruction currently being executed

13. Main Memory Directly connected to the CPU
All programs must be loaded into main memory before they can be executed
All data must be brought into main memory before it can be manipulated
When computer power is turned off, everything in main memory is lost

15. Secondary Storage
Secondary storage: Device that stores information permanently
Examples of secondary storage:
Hard disks
Floppy disks
Zip disks
CD-ROMs
Tapes
Flash drives

16. Input/output Devices
Input devices feed data and programs into computers. They include:
Keyboard
Mouse
Secondary storage
Output devices display results. They include:
Monitor
Printer

17. Software Software: Programs that do specific tasks
1. System programs take control of the computer, such as an operating system
Operating System monitors the overall activity of the computer and provides services.
2. Application programs perform a specific task
Word processors
Spreadsheets
Games

18. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

19. The Language of a Computer
Digital signals are sequences of 0s and 1s
Machine language: language of a computer
Binary digit (bit):
The digit 0 or 1
Binary code:
A sequence of 0s and 1s
Byte:
A sequence of eight bits

21. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

22. Programming Language Evolution
Early computers were programmed in machine language
To calculate wages = rates * hours in machine language:
//Load
//Multiply
//Store
C++ Programming: From Problem Analysis to Program Design, Third Edition

23. Assembly Language Assembly language instructions are mnemonic.
Mnemonic (easy-to-remember).
Assembler: translates a program written in assembly language into machine language

24. High-Level Languages
High-level languages include Basic, FORTRAN, COBOL, Pascal, C++, C, and Java
Compiler: translates a program written in a high-level language machine language
The equation wages = rate • hours can be written in C++ as:
wages = rate * hours;

25. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

26. A C++ Program Sample Run: #include <iostream>
using namespace std;
int main() {
cout << "My first C++ program." << endl;
cout << "The sum of 2 and 3 = " << 5 << endl;
cout << "7 + 8 = " << << endl;
return 0; }
Sample Run:
My first C++ program.
The sum of 2 and 3 = 5
7 + 8 = 15

27. A C++ Program cout << "My first C++ program." << endl;
This is a C++ output statement.
It causes the computer to
evaluate the expression after the pair
of symbols << and
display the result in the screen.
endl causes the insertion point
to move to the beginning of the
next line.
C++ contain various types of
Expressions such as arithmetic and
strings. For example: 7+8 is arithmetic
expression. Anything in double quotes
is a string “7+8” is a string

28. A C++ Program Sample Run:
cout << "My first C++ program." << endl;
Sample Run:
My first C++ program.

29. A C++ Program Sample Run:
cout << "The sum of 2 and 3 = " << 5 << endl;
Sample Run:
The sum of 2 and 3 = 5
The first expression
“The sum f 2 and 3 = “ is
a string and evaluates to
itself .
The second expression consists of
Number 5 and evaluates to itself.

30. A C++ Program Sample Run:
cout << "7 + 8 = " << << endl;
Sample Run:
7 + 8 = 15
The first expression
“7 + 8 = “ is a string and
evaluates to itself.
The second expression consists of
number 7 and 8, and the C++ arithmetic
operator +. Therefore the result of the
expression is the sum of 7 and 8 which
is 15.

31. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

32. Processing a Program Editor
The following steps are necessary to process a program in C++:
Editor
Step 1: Use text editor to create a C++ program. This program is called source code or source program.

33. Processing a Program
Step 2: In a C++ program, statements that begin with the symbol # are called preprocessor directives. These statements are processed by a program called preprocessor.

34. Processing a Program Step 3: Compiler is used to:
verifies that the program obeys the rules of the programming language and checks the source program for syntax errors.
Translate the program into equivalent machine language (object program).

35. Processing a Program
Step 4: Programs in high level languages are developed using a software development kit (SDK).
SDK contains programs that are useful in creating your program such as mathematical functions.
The prewritten code resides in a library.
Linker combines the object code with the program from libraries.

36. Processing a Program
Step 5: You must load the executable program into main memory for execution. Loader: a program that loads an executable program into main memory.

37. Processing a Program
Step 6: The final step is to execute the program.

38. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

39. Problem Solving Programming is a process of problem solving
Problem solving techniques
Analyze the problem
Outline the problem requirements
Design steps (algorithm) to solve the problem
Algorithm:
Step-by-step problem-solving process
Solution achieved in finite amount of time

40. Problem Solving Process
Step 1 - Analyze the problem
Outline the problem and its requirements
Design steps (algorithm) to solve the problem
Step 2 - Implement the algorithm
Implement the algorithm in code
Verify that the algorithm works
Step 3 - Maintenance
Use and modify the program if the problem domain changes

41. Example
Design algorithm to find the perimeter and area of a rectangle.
Analyze the problem:
To find the perimeter and area of a rectangle, we need to know the rectangle’s length and width.
The perimeter and area of rectangle is given by the following formula:
Perimeter = 2 . (length + width)
Area = length . width

42. Example (continues) Design algorithm: Get length of Rectangle.
Get width of Rectangle.
Find the perimeter using the following equation: Perimeter = 2 . (length + width)
Find the area using the following equation:
Area = length . width

44. Compiling and Linking Run code through compiler
If compiler generates errors
Look at code and remove errors
Run code again through compiler
If there are no syntax errors
Compiler generates equivalent machine code
Linker links machine code with system resources

45. Outline 1. Overview of the History of Computers.
2. Elements of a Computer System.
3. The language of a computer.
4. The Evolution of Programming Languages.
5. A C++ Program.
6. Processing a Program.
7. Analysis-Coding-Execution Cycle.
8. ANSI/ISO Standard C++.

46. ANSI/ISO STANDARD C++ C++ evolved from C
C++ designed by Bjarne Stroustrup at Bell Laboratories in early 1980s
C++ programs were not always portable from one compiler to another
In mid-1998, ANSI/ISO C++ language standards were approved

47. Summary
Computer: an electronic device that can perform arithmetic and logical operations
Computer system has hardware and software
Central processing unit (CPU): brain
Primary storage (MM) is volatile; secondary storage (e.g., disk) is permanent
Operating system monitors the overall activity of the computer and provides services

48. Summary (continued)
Various kinds of languages, such as machine language, assembly, high-level
The problem-solving process has three steps:
Analyze problem and design an algorithm
Implement the algorithm in code
Maintain the program