Recursion used in C language

What is recursion in C ?

When a function call to itself or when a function call to a second function and in function definition of second function again a function call statement for first function is encountered, it is known as recursion and this types of function is called recursive function.

Types of recursion in C ?

1. Direct recursion :

                ABC ()

                {

                 "

                 "

                 "

                ABC () ;

                }

2. Indirect recursion :

                ABC ()
                  {
                   "
                   XYZ () ;
                   "
                 XYZ ()
                 {
                 "
                ABC () ;
                "

Program of recursive function to find factorial in C:

#include < stdio.h>

int factorial ( int ) ;

void main ()

{

int a , b ;

printf ("\n Enter a number:") ;

scanf ("%d", &a) ;

b = factorial (a) ;

printf ("%d" , b) ;

getch () ;

}
int factorial ( int a )

{

if ( a == 0 )

return 1 ;

else

return ( a * factorial ( a - 1 ) ) ;

}