ProjectEuler problem 3 (unverified)

/* ProjectEuler.net Problem 3

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143 ? */
#include <stdio.h>
#include <cstdlib>
int findThatLargestPrime(const long &hugeNumber)
{
    static long thatPrime = hugeNumber - 1;
    do { thatPrime--; } while (hugeNumber%thatPrime);
    bool didItFail=false;
    for ( long i=thatPrime-1; i == 2; i-- )
    {
        long primeTest = thatPrime%i;
        if (!primeTest)
        {
            didItFail=true;
            break;
        }
    }
    if (!didItFail) { printf("%lu is a factor but is not prime\n",thatPrime); return -1; } else { return thatPrime; }
}

int main(int argc, char *argv[])
{
    const ulong bigNumber = 600851475143;
    long hitGold;
    do {
        hitGold = findThatLargestPrime(bigNumber);
    } while (hitGold==-1);
    printf("%ld\n",hitGold);
    return 0;
}