#include<stdio.h>
#include<conio.h>
void main ()
{
int n;
int sum (int) ;
clrscr () ;
printf("Enter the number : ");
scanf("%d",&n);
printf("Sum of %d natural numbers = %d",n,sum(n)) ;
getch () ;
}
int sum ( int n )
{
int s = 0 ;
if ( n == 0 )
return ( 0 ) ;
else s = n + sum (n-1) ;
return ( s ) ;
}