Write a First program in C/C++

Welcome back! In my first post, I tell you that C++ is a advanced version of C. It means that you must learn C language before starting C++.

First of all, We should know about a C program structure that is shown below:

A program is made up of different parts, which are as follow:

• Documentation section:- Under this section, Programmer writes information related to his program such as- the purpose of writing programs, date of creation and programmer's name etc. To write an information such as  /*...............*/
• Link section:- Under this section, the Header files(Input/output library) used in the program are added. Header files(I/O library) are of the following type.

       #include<stdio.h>
       #include<conio.h>
       #include<math.h>
       #include<graphics.h>......etc.

Note: A library is simply a package of code that someone else has wrriten to make coding easier. 

• Defination section:- Constant value is defaced under this section such as:

       #define pi=3.14

• Global variable declration section:- Global variable is a variable that can be used in any part of the program. All global variables in the program are declared under this section.
• Main Function:- This is the main part of the program and the implementation of the program starts with this, it has two parts:

     i) Declration part:- The variables used in this part are declared.
    ii) Executable part:- Various actions in the program are displayed in this              section.

Example:

/* PROGRAM FOR ADD TWO NUMBERS*/                                                         

  #include<stdio.h>                                                                                       

  #include<conio.h>                                                                                      

      void main() 
 {                                                                                            

      int num1, num2, sum;                                                                             

      clrscr();                                                                                                  

      printf("Enter the two integer values to be added");                                     

      scanf("%d%d", &num1, num2, sum);                                                       

      sum=num1+num2;                                                                                       printf("Addition of %d and%d is %d\n", num1, num2, sum);                      

      getch();                                                                                                  

  }