#include <iostream>
#include <cmath>                  //sqrt
#include <cstdlib>               //EXIT_SUCCESS
using namespace std;int main(){float a,b,c,discriminant,x1,x2;char again='y';while(again=='y'){cout<<"Enter a: ";cin >> a;while(a==0){cout<<"ERROR.  a can not be zero.  Re-enter a: ";cin>>a;}cout<<"Enter b and c: ";cin>>b>>c;discriminant = b*b - 4*a*c;if(discriminant > 0) {x1=(-b+sqrt(discriminant))/(2 * a); x2 = (-b - sqrt(discriminant))/(2 * a);cout<< "x1: " << x1 << "    x2: " << x2 << endl;}else if (discriminant == 0){x1=-b/(2*a);cout << "x= " << x1 << endl;}else cout << "Discriminant is negative." << endl;cout << endl << "Again? (y or n): ";cin>>again;}return EXIT_SUCCESS;}