题解 | #求解立方根#

#include <iostream>
using namespace std;

#define Epison 1e-7

int main() {
    double n;
    cin >> n;
    double temp =n;
    double res;    
    if(n <Epison){
        n =-n;
    }
    double m;
    for (int i = 0; i < 21; i++) {
        if (i * i * i > n) {
            m = i - 1;
            break;
        }
    }
    for (double j = m; j < m+1.1; j += 0.1) {
        if (j * j * j > n) {
            if ((j * j * j) - n< n - ((j - 0.1) * (j - 0.1) * (j - 0.1)))  res=j;
            else res =j -0.1;
            break;
        }
    }
    if(temp >=Epison) cout << res;
    else cout << -res;
}