1. Program to find the greatest common divisor (GCD).
#include <iostream.h>
#include <conio.h>
int gcd(int a, int b) {
if (b == 0)
return a;
return gcd(b, a % b);
}
int main() {
int num1, num2, result;
cout << "Enter two numbers: ";
cin >> num1 >> num2;
result = gcd(num1, num2);
cout << "GCD of " << num1 << " and " << num2 << " is " << result << endl;
getch();
return 0;
}