C PROCESSOR DIRECTIVES

• Preprocessor Directive Always begins with # Symbol.
• Preprocessor Directive basically two categories macro expansion & file inclusion.
• #define used for macro expansion & #include used for file inclusion.
• #define directive also used for global variable.

Example1
#include<stdio.h>
#include<conio.h>
#define pi 3.14
#define Upper 25 //global variable
#define msg "C is Developed By Dennis Ritcihe"
void main()
{
clrscr();
printf("pi = %f",pi);
printf("\nupper = %d",Upper);
printf("\nMsg = %s",msg);
getch();
}

Example2

#include<stdio.h>

#include "conio.h"

#define ashok printf("C is procedural programming language");

void main()

{

clrscr();

ashok;

getch();

}

Example3

#include<stdio.h>

#include "conio.h"

#define area(r) (3.14*r*r)

void main()

{

clrscr();

printf("\nArea of Circle = %f",area(2));

getch();

}