// File: quadratic.cxx
// Michael Main (main@colorado.edu)
// THis program prints the two real roots of a quadratic
// equation.  It illustrates an "if ... else" statement.

#include <iostream> // For cin, cout
#include <cmath>    // For sqrt()
using namespace std;

int main( )
{
    double a, b, c;      // Coefficients of a quad. equation
    double discriminant; // Value of b*b - 4ac
    double root;         // One root of the quadratic equation

    // Read the input.
    cout << "Please type the abc coefficients of a quadratic\n";
    cout << "equation of the form a*x*x + b*x + c = 0.\n";
    cout << "Enter a b c: ";
    cin >> a >> b >> c;

    // Calculations, using a repeated if-else
    discriminant = b*b - 4*a*c;
    if (a == 0)
    {
	cout << "This program can't handle a == 0.\n";
    }
    else if (discriminant < 0)
    {
	cout << "That equation has no real roots.\n";
    }
    else
    {
	root = (-1.0*b + sqrt(discriminant)) / (2*a);
	cout << "First root is: " << root << endl;
	root = (-1.0*b - sqrt(discriminant)) / (2*a);
	cout << "Second root is: " << root << endl;
    }

    return 0;
}