Binary Power

fast_power.cpp

#include <vector>
#include <iostream>

using ull = unsigned long long;

ull fast_power(ull num, int power)
{
    if(num < 0 || power < 0) {
        std::cout << "invalid arguments specified\n";
    }
    
    int k = power;
    ull b = 1;
    ull c = num;
    
    while(k != 0)
    {
        if (k % 2 == 0)
        {
            k /= 2;
            c *= c;
        }
        else 
        {
            k--;
            b *= c;
        }
    }
    
    std::cout << "b = " << b << "\nc = " << c << "\n";
}

int main()
{
    fast_power(45, 6);

    return 0;
}