/* Implement sum of the first n natural numbers recursively
   Emad Arasteh
   November 21 , 2019
*/
#include <stdio.h>

int sum(int n)
{
  /* uncomment the print to see all the function calls */
  /* printf("sum function call for %d!\n", n); */
  if (n == 1) {
      return 1;
  }
  else {
    return (n + sum(n-1));
  }
}

int main()
{
  int n, result;
  printf("Please enter a natural number: ");
  scanf("%d", &n);
  result = sum(n);
  printf("Sum of the first %d natual numbers is %d \n", n, result);
  return 0;
}