let's code: square root function in c++

#include <iostream>
#include <cmath>

using namespace std;

int main(void) {
        float value, square_root;

        cout << "Enter your number now: " << endl;
        cin >> value;
        if(value >= 0.0) {
            square_root = sqrtf(value);
            cout << "You have entered: " << value << endl;
            cout << "Your square root is: " << squareroot << endl;
        }
        return 0;
}