C program to find hcf and lcm using recursion.

#include <stdio.h>

 #include<conio.h>

long gcd(long, long);

int main() {

  long x, y, hcf, lcm;

  clrscr();

  printf("Enter two integers\n");

  scanf("%ld%ld", &x, &y);

  hcf = gcd(x, y);

  lcm = (x*y)/hcf;

  printf("Greatest common divisor of %ld and %ld = %ld\n", x, y, hcf);

  printf("Least common multiple of %ld and %ld = %ld\n", x, y, lcm);

  getch();

}

long gcd(long a, long b) {

  if (b == 0) {

    return a;

  }

  else {

    return gcd(b, a % b);

  }

}

Output:-

Enter two integers

9

24

Greatest common divisor of 9 and 24 = 3

Least common multiple of 9 and 24 = 72