Сверхдлинные суммы

#include <iostream>
#include <conio.h>

using namespace std;

int a, b, c[1000001];

int main()
{
    int
        long long n, x = 0;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> a >> b;
        c[i] = a + b;
    }

    for (int i = n; i >= 1; i--)
    {
        if (c[i] + x < 10)
        {
            c[i] = c[i] + x;
            x = 0;
        }
        else
        {
            c[i] = c[i]+x - 10;
            x = 1;
        }
    }
    if (x == 1) cout << 1;
    for (int i = 1; i <= n; i++)
        cout << c[i];

    _getch();
    return 0;
}