Fix the program

This program is supposed to output the factorial of 5. However, the function factorial is flawed. The flaw is causing it to infinitely loop.

Analyze the program and fix the function.

#include <iostream>

unsigned long long factorial(int N)
{
    if (N == 1) 
        return 1; 
 
    return N * factorial(N);
}

int main()
{
    std::cout << "Factorial of 5: " << factorial(5) << "\n";
}

Hint

The value of N is never changed. This leads to it never reaching 1, which is the condition for reaching the base case.

Answer

#include <iostream>

unsigned long long factorial(int N)
{
    if (N == 1) 
        return 1; 
 
    return N * factorial(N-1);
}

int main()
{
    std::cout << "Factorial of 5: " << factorial(5) << "\n";
}

Changing factorial call inside factorial to pass N-1 instead of just N makes sure that N eventually reaches 1, preventing the loop from continuing forever.