Recursion

Recursion is a programming technique that allows the programmer to express operations in terms of themselves. Simply we can say that when a 'c' function calls itself.
In other words recursion is thus the process of defining something in terms of itself.

Recursive functions

void recurse()
{
    recurse(); /* Function calls itself */
}

void main()
{
    recurse(); /* Sets off the recursion */
    getch();
}

We want to calculate the factorial value using recursive function.

#include<stdio.h>
#include<conio.h>
void main( )
{
	int num, factorial ;
	clrscr();
	printf ( "\nEnter any number " ) ;
	scanf ( "%d", &num ) ;
	factorial = fact ( num ) ;
	printf ( "Factorial value = %d", factorial ) ;
	getch();
}
fact ( int n )
{

	if ( n == 0 )
		return ( 1 ) ;
	else
		return(n * fact ( n - 1 ) ;
}

Output

Explaination

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