Second function with same integers doesn't work

Question

I have a task to create 2 functions to calculate GCD and LCM. But I noticed that my second function doesn't work not matter what calculation is there. What am I doing wrong?

#include <iostream>
using namespace std;

int gcd(int number1,int number2);


int lcm(int number1,int number2);

int main()
{

    int number1;
    int number2;
    cout<<"enter number 1: ";
    cin>>number1;
    cout<<"enter number 2: ";
    cin>>number2;
    cout<<"The GCD of "<<number1<<" and "<<number2<<" is "<<gcd(number1,number2)<<endl;
    cout<<"The LCM of "<<number1<<" and "<<number2<<" is "<<lcm(number1,number2)<<endl;

    return 0;
}
    int gcd(int number1,int number2)
    {
        if (number2==0)
            return number1;
        return gcd(number2,number1 % number2);
    }

    int lcm(int number1,int number2)
    {
        return lcm(number2, number1 * number2)/gcd(number1,number2);
    }

Output:

 enter number 1: 44 enter number 2: 121 The GCD of 44 and 121 is 11 The LCM of 44 and 121 is Process returned -1073741571 (0xC00000FD)

Answer 1

The problem lies within the lcm() function:

int lcm(int number1,int number2)
{
    return lcm(number2, number1 * number2)/gcd(number1,number2);
}

This function will be an infinite recursion because there's no base case. Eventually, you will run into, ironically, a stack overflow problem.

Looking at the nature of the function, I think what you meant is:

int lcm(int number1, int number2)
{
    return number1 * number2 / gcd(number1, number2);
}

Answer 2

I believe this is what you wanted to do in your function?

 #include <iostream> using namespace std; int gcd(int number1,int number2); int lcm(int number1,int number2); int main() { int number1; int number2; cout<<"enter number 1: "; cin>>number1; cout<<"enter number 2: "; cin>>number2; cout<<"The GCD of "<<number1<<" and "<<number2<<" is "<<gcd(number1,number2)<<endl; cout<<"The LCM of "<<number1<<" and "<<number2<<" is "<<lcm(number1,number2)<<endl; return 0; } int gcd(int number1,int number2) { if (number2==0) return number1; return gcd(number2,number1 % number2); } int lcm(int number1,int number2) { int lcmResult=number1 * number2/gcd(number1,number2); return lcmResult; }

and the output i got is:

 enter number 1: 44 enter number 2: 121 The GCD of 44 and 121 is 44 The LCM of 44 and 121 is 121