acwing 790. The cubic root of a number (floating-point number in half)

Given a floating-point number n, Find its third root .

Input format
All in one line , Contains a floating-point number n.

Output format
All in one line , Contains a floating-point number , Represents the solution of the problem .

Be careful , The result is reserved 6 Decimal place .

Data range
−10000≤n≤10000
sample input ：
1000.00
sample output ：
10.000000

Ideas ： Just two points
Remember to use the variable double type

Picture understanding ：

#include <iostream>

using namespace std;

int main()
{
    
    double x;
    cin >> x;
    
    double l = -10000, r = 10000;  //  Take the range of the result directly 
    while(r - l > 1e-8)  //  Empirical value ：  If you keep a few decimal places ,  Once again, add 2 The negative power of 
    {
    
        double mid = (l + r) / 2;   //  There can no longer be int  Variable 
        if( mid * mid * mid >= x) r = mid;
        else l = mid;
    }
    
    printf("%lf\n", r); //  Write here l  perhaps  r  Will do 
    return 0;
}