Factorial.cpp

#include <iostream>
#include "BigFloat.h"

BigFloat factorial(const BigFloat& n)
{
    if(n > 1)
        return n * factorial(n - 1);
    else if(n == 0)
        return 1;
    else
        return n;
}

int main()
{
    //For reference, execution times on an old Core 2 Duo
    //200!  --> 375 digits  - no optimization: 5 seconds
    //300!  --> 615 digits  - no optimization: 20 seconds,   compiled with -O3: 1 seconds
    //500!  --> 1135 digits - no optimization: 115 seconds,  compiled with -O3: 4 seconds
    //1000! --> 2568 digits - no optimization: 1200 seconds, compiled with -O3: 47 seconds
    BigFloat fact, num(1000);
    fact = factorial(num);
    std::cout << fact << std::endl;
    std::cout << fact.Ints() << std::endl;
    return 0;
}