数的三次方根

求浮点数 n的三次方根

#include <iostream>
using namespace std;
double n;

double BF (double x) {
    double l = -100, r = 100;
    while (r - l > 1e-8) {
        double mid = (l + r) / 2;
        if (mid * mid * mid < x) l = mid;
        else r = mid;
    }
    
    return l;
}

int main() {
    double x;
    cin >> x;
    printf("%.6lf\n", BF(x));
    return 0;
}