Project Euler - Problem 3 - Largest prime factor

p3_projecteuler.cpp

/* 
Project_3.cpp : Largest prime factor
The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of the number 600851475143 ?
*/

#include <iostream>
using namespace std;

int main()
{
	long long num, factor = 2; // type is "long long" as it is a huge number
	cout << "Enter the number to see the largest prime factor: ";
	cin >> num; // I prefered user entered number. Here the given number can be entered.

	while (num != 1) // until division is done
	{
		if (num % factor == 0) 
		{
			num /= factor;
		}
		else
			factor++;
	}

	cout << "Largest prime factor is " << factor << endl;

    return 0;
}