以下是程式碼

#include <iostream>
using namespace std;
int main(){

    do{
        double a, b, c;
        double x, y;
        cin >> a >> b >> c;
        x = ((-b) + sqrt((b*b) - (4 * a*c))) / 2 * a;
        y = ((-b) - sqrt((b*b) - (4 * a*c))) / 2 * a;
        if (x != y)
        cout << "Two different roots x1 = " << x << ", x2 = " << y << endl;
        else if (x == y)
        cout << "Two same roots x = " << x << endl;
        else
        cout << "No real root" << endl;
        } while (1);
    return 0;
}

答案都對阿~但為啥不過呢?