Basic structure of a “C” program:-

Documentation Section	/* Program for addition of 2 numbers */
Link Section (or)  Preprocessor Directives	#include<stdio.h> #include<conio.h>
Definition section	#define pf printf
Global Declaration Section
Main() Function Section                       main()            {               Declaration part;               Execution part;            }	Main() Function Section       main()      {        int a,b,c;        clrscr();        printf(“Enter a and b values:”);        scanf(“%d%d”,&a,&b);        c=a+b;        printf(“sum is %d”,c);     }
Sub Program Section (or) User-defined function Section Function 1 Function 2 ----------------- Function n

Write a “C” program to print a message.

Method 1:-
/*print a message 

  of your choice */
#include<stdio.h>
#define pf printf
main()
{
pf(“welcome to “C”);
}
Method 2:-
//print a message
#include<stdio.h>
#define pf printf
Void main()
{
pf (“welcome to “C”);
}
Method 3:-
//print a message
#include<stdio.h>
#define pf printf
int main()
{
Pf(“welcome to “C”);
return 0;
}

/* Program to illustrate the different data types and there number of bytes occupied */
#include<stdio.h>
#include<conio.h>
void main()
{
 int a=22;
 char b[]="raj kumar";
 char c='f';
 float d=143.5;
 double e=1234.54;
 clrscr();
 printf("\n the string is : %s",b);
 printf("\n the character is :%c",c);
 printf("\n the number of bytes occupied by char is :%d",sizeof(c));
 printf("\n");
 printf("\n the integer is %d",a);
 printf("\n the number of bytes occupied by int is :%d",sizeof(a));
 printf("\n");
 printf("\n the float value is %f",d);
 printf("\n the number of bytes occupied by flaot is :%d",sizeof(d));
 printf("\n");
 printf("\n the double value is %lf",e);
 printf("\n the number of bytes occupied by double is :%d",sizeof(e));
 getch();
}

output:

//Program to illustrate the Local and Global variables 

#include<stdio.h>

#include<conio.h>

int global;

void main()

{

 int local;

 clrscr();

 printf("\n the local variable is : %d",local);

 printf("\n the global variable is : %d",global);

 getch();

}

output: