JavaSection110

// Guide to Java
// Copyright 2014, by J.T. Streib and T. Soma

// A program to calculate two roots of a quadratic equation.
// Assume that a <> 0 and the relationship b^2 >= 4ac holds,
// so there will be real number solutions for x.

import java.util.*;

class QuadEq {
  public static void main(String[] args) {

     // declaration and initialization of variables
     double a, b, c, root1, root2, sqrtDiscr;
     Scanner scanner;
     scanner = new Scanner(System.in);

     // input a, b, and c
     System.out.print("Enter a: ");
     a = scanner.nextDouble();
     System.out.print("Enter b: ");
     b = scanner.nextDouble();
     System.out.print("Enter c: ");
     c = scanner.nextDouble();

     // compute the two roots
     sqrtDiscr = Math.sqrt(Math.pow(b,2) - 4*a*c);
     root1 = (-b + sqrtDiscr) / (2*a);
     root2 = (-b - sqrtDiscr) / (2*a);

     // output the two roots
     System.out.println();
     System.out.println("Two roots of the equation, " + a
                       + "*x*x + " + b + "*x + " + c + " = 0, are");
   System.out.printf("%.2f and %.2f.", root1, root2);
}
}