Gaussian

namespace myfuncs {
    // calculate the power
    double pow(double x, int n) {
        double result = 1;
        for (int i = 0; i < n; i++) {
            result *= x;
        }
        return result;
    }

    double gaussian(double x, double eps) {
        double result = 0;
        double term = 1;
        int n = 0;
        while (term > eps) {
            term = pow(x, 2 * n + 1) / (2 * n + 1);
            result += term;
            n++;
        }
        return result;
    }
}