Estimate e with Taylor Series

#include <iostream>

using namespace std;

int main(int argc, char const* argv[])
{
    double e = 1, dlt = 1;

    int fact = 1;
    int idx = 1;

    while (dlt > 1e-7) {
        fact *= idx++;
        dlt = 1.0 / fact;
        e += dlt;
    }

    cout << e << endl;

    return 0;
}