Question

 Explain the syntax of C++ program structure with example. 

Answer 1

 1) A typical C++ program contains 4 sections as shown in following figure. These sections may be placed in different code files and then compiled independently or jointly.

Include files

Class declaration

Class functions definitions

Main function program

                Structure of C++ program 

2) It is a common practice to organize a program into three separate files.
3) The class declarations are placed in a header file and the definitions of the member go in other file.
4) This approach enables the programmer to separate the abstract of the interface from the implementation details.
5) Finally the main program that uses the class is placed in third file, which includes the previous two files as well as any other files required. 

Example : 
# include <iostream.h>
# include <conio.h>
# include <math. h>
class triangle
{
private:
float a, p, x, y, z;
public :
void accept ()
{
cout <‘’Enter three sides of triangle’’;
cin >> x>> y>>z;
}
void compute()
{p = x+y+z;
double & = P/2;
a = sqrt(s*(s-a)*(s-b)*(s-c));
cout <<‘’Area’’<<a;
}
};
void main()
{clrscr();
triangle t1;
t1.accept();
t1.compute();
getch();
}