/* Sum of natural numbers - Write a recursive function to calculate 1+2+3+...+n */

#include  <stdio.h>
#include  <conio.h>

long  sum(int  n)
{
    if(n==1)
        return  1 ;
    else
        return ( n + sum(n-1) ) ;
}

void main()
{
    int  n ;
    clrscr() ;
    printf("Enter n: ") ;
    scanf("%d", &n) ;
    printf("Sum of first %d natural numbers is %ld", n, sum(n) ) ;
    getch() ;
}

/*
Output:

Enter n: 3
Sum of first 3 natural numbers is 6
*/