Global or External variables :

Variables are declared outside the body of the main program are referred as global variables.

Example :

/* Description: write a simple program use global or external variable */ #include<stdio.h> int age=23; main() { printf("My age is %d.",age); getch(); }

Note : Global variable values can be referred in a function. They need not be passed to the function as arguments.

Output :

void function :

A function which does not return a value directly to the calling program is referred as a void function.

Example :

/* Description: write a simple program use void function */ #include<stdio.h> int m,n; main() { void add(void); m=10,n=20; printf("\n m = %d and n = %d",m,n); add(); printf("\n m = %d and n = %d",m,n); getch(); } void add() { m = m + 15; n = n + 15; }

Note : A void function can also use a return statements without a return value (return;).

Output :