Thread: Having some problem with a GCF program

So, I am new to C++ and only just started. I have bought a book called C++ Without Fear by Brian Overland, and I am having a problem with one of the exercises to do with the Greatest Common Factor.

The source code is:

Code:

#include <iostream>
using namespace std;

int gcf(int a, int b);

int main() {
    int a = 0, b = 0;
    while(1) {
        cout << "Enter a number (0 to quit): ";
        cin >> a;
        if (a==0)
        break;
        cout << "Enter 2nd number: ";
        cin >> b;
        cout << "GCF = " << gcf(a, b) << endl;
    }
    return 0;
}

int gcf(int a, int b) {
    if (a % b == 0)
    return b;
    else
    return gcf(b, a % b);
    cout << gcf(b, a % b);
}

That much I have managed to understand, but now after he explains it, he says to do an exercise where I revise the program so it shows all the steps involved in the algorithm.

For example-
GCF(300, 500) =>
GCF(500, 300) =>
GCF(300, 200) =>
GCF(200, 100) =>
GCF = 100

Right now, all that the code does is immediately give the answer.
Please help me out.

Thanks!

Thanks, working fine now