C program to find HCF and LCM: The code below finds the highest common factor and the least common multiple of two integers. HCF is also known as the greatest common divisor (GCD) or the greatest common factor (GCF).

## HCF of two numbers in C

int main() {

int a, b, x, y, t, gcd, lcm;

printf("Enter two integers\n");

scanf("%d%d", &x, &y);

a = x;

b = y;

while (b != 0) {

t = b;

b = a % b;

a = t;

}

gcd = a;

lcm = (x*y)/gcd;

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

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

return 0;

}

Download HCF and LCM program.

Output of program:

## C program to find hcf and lcm using recursion

long gcd(long, long);

int main() {

long x, y, hcf, lcm;

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);

return 0;

}

long gcd(long a, long b) {

if (b == 0)

return a;

else

return gcd(b, a % b);

}

## C program to find hcf and lcm using function

long gcd(long, long);

int main() {

long x, y, hcf, lcm;

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);

return 0;

}

long gcd(long x, long y) {

if (x == 0) {

return y;

}

while (y != 0) {

if (x > y)

x = x - y;

else

y = y - x;

}

return x;

}