Factorial of 500!

Problem link: UVa 623 - 500!

                                HackerRank - Extra Long Factorial

#include <bits/stdc++.h>

using namespace std;

int main()

{

int n;

while (cin >> n)

{

int arr[1000000];

int carry = 0, k = 0;

arr[0] = 1;

for (int i = 1; i <= n; ++i)

{

for (int j = 0; j <= k; ++j)

{

arr[j] = arr[j] * i + carry;

carry = arr[j] / 10;

arr[j] = arr[j] % 10;

}

while (carry)

{

k++;

arr[k] = carry % 10;

carry /= 10;

}

}

cout << n << "!" << endl;

for (int i = k; i >= 0; --i)

cout << arr[i];

cout << endl;

}

return 0;

}