This document discusses the components of a C++ program structure and the process of using a compiler. It identifies that a C++ program consists of comments, preprocessor directives, functions, bodies, and return statements. It then explains each of these components and provides examples. The document also outlines the steps to build a C++ program using a compiler which are editing source code, compiling to object code, linking to an executable, and executing the program.

1. 8.3 Introduction to C++
8.3.1 Program Structure
8.3.2 Using Compiler

2. 8.3.1 Program Structure
• Learning Outcome
– Identify the component of C++
i. comment
ii. preprocessor directive
iii. function
iv. body
v. return statement

3. 8.3.1 Program Structure
• A computer program consists a list of
instructions written in a computer language.
//This is my first C++ program
//It prints a line of text i. comment
#include <iostream.h> ii. preprocessor
#include <stdlib.h> directive
int main()
iii. function
{
cout << "My first C++ program" ;
iv. body
system("PAUSE");
return 0; v. return
}
Fig. 1 : Example 1 statement

4. 8.3.1 Program Structure
// height.cpp i. comment
// Convert height in feet to inches
#include <iostream.h> ii. preprocessor
#include <stdlib.h> directive
int main()
iii. function
{
int feet, inches;
inches = feet * 12;
cout << “Enter feet value : ”;
cin >> feet;
cout << “Height is“ << inches ; iv. body
cout << “in.” ;
system("PAUSE");
return 0; v. return
} Fig. 2: Example 2 statement

5. 8.3.1 Program Structure
• comment
//This is my first C++ program
//It prints a line of text
/*This is my first C++ program
It prints a line of text */
• Style to insert a comment in C++.
– Text begin with two double slash (//) -
normally used for single line comment
– Text begin with /* and ends with */ - possibly
containing many lines

6. 8.3.1 Program Structure
i. comment
• The purpose to insert a comment
– To document a program
– To improve program readability – help other
people read and understand a program.
• Remember – comment do not cause the
computer to perform any action when the
program is run.

7. 8.3.1 Program Structure
i. preprocessor directive
- Preprocessor directive is a general instruction
to the C++ compiler
- # :are processed by preprocessor before
program is compiled.
- #include <iostream.h> :tells the
preprocessor to include in the program the
contents of the input/output stream header
file iostream.h

8. 8.3.1 Program Structure
i. preprocessor directive
- iostream.h
:specific file needed for programs that either
input data from keyboard or write output on the
screen.
:called as header file ( with the file extension .h)
:other examples
:#include <stdlib.h>
:#include <math.h>

9. 8.3.1 Program Structure
i. function
int main()
: the parentheses, () after main indicate that
main is a program building block called a
function.
: example given on Fig. 1; contain only one
function.
: C++ programs normally begin executing at
function main.

10. 8.3.1 Program Structure
i. Body
: the left brace, {, must begin the body of every
function.
: a corresponding right brace, }, must end the
body of each function.
: examples: Refer to Fig.1 and Fig.2 ( body
segment )

11. 8.3.1 Program Structure
i. Body
: The body of main may consist of:
i) variable declaration and reserve word
e.g. : int feet, inches;
reserved word variables

12. 8.3.1 Program Structure
i. Body
: The body of main may consist of:
ii) input / output console
input console: use standard input stream object -
cin and input operator, >>, to allow user type in
a value (or values)
e.g. : cin >> feet;

13. 8.3.1 Program Structure
i. Body
: The body of main may consist of:
ii) input / output console
output console: use use standard output stream
object - cout and the output operator, <<, to
output the message.
e.g. : cout << “Height is“ <<inches;

14. 8.3.1 Program Structure
i. Body
: The body of main may consist of:
iii) C++ statement
: Every statement must end must end with
semicolon (;).
e.g. :
i. cout <<"My first C++ program”;
ii. inches = feet * 12;

15. 8.3.1 Program Structure
i. return statement
return 0;
: is included at the end of main function.
: the C++ keyword return statement is used at
the end of main, the value 0 indicates that
the program has terminated successfully.
:the right brace,}, indicates the end of main.

16. 8.3.2 Using Compiler
• Learning Outcome
– Edit
– Compile
– Link
– Execute program

17. 8.3.2 Using Compiler
program.cpp C++ program.obj
(C++ source code) compiler (object code)
Linker
C++ Library
program.exe
(executable program)
Fig. 1: Building a C++ Program

18. 8.3.2 Using Compiler
• Edit – enter the program statement
• To write a C++ program, you need to enter the
program statements by using:
– Text editor (e.g. Notepad, Microsoft Word etc.)
– Integrated Development Environment (IDE)(e.g.
Dev C++, Borland C++ etc.)
• The complete program statements called
“source code”.
code

19. 8.3.2 Using Compiler
• Compile – translating C++ into machine code
Compil
(also called “object code”)
– Compiler determines the syntax error.
• Link – Run the linker – combine the machine
code with code from C++ library; after
compiles is successful.

20. 8.3.2 Using Compiler
• Execute Program – an application can be run.
– Finally, the computer, under the control of its
CPU, executes the program one instruction at a
time.
Remember :
Compiler detects grammatical (syntax) error NOT
the program-logic error

21. 8.3.2 Using Compiler
Tool Step Product
Editor Edit
Source code
Compiler Compile
Object code
Linker Link
Executable image
Run
Result / Output