Quadratic.java

/******************************************************************************
 *  Compilation:  javac Quadratic.java
 *  Execution:    java Quadatic b c
 *  
 *  Given b and c, solves for the roots of x*x + b*x + c.
 *  Assumes both roots are real valued.
 *
 *  % java Quadratic -3.0 2.0
 *  2.0
 *  1.0
 *
 *  % java Quadratic -1.0 -1.0
 *  1.618033988749895
 *  -0.6180339887498949
 *
 *
 *  % java Quadratic 1.0 1.0
 *  NaN
 *  NaN
 *
 *
 ******************************************************************************/

public class Quadratic { 

    public static void main(String[] args) { 
        double b = Double.parseDouble(args[0]);
        double c = Double.parseDouble(args[1]);

        double discriminant = b*b - 4.0*c;
        double sqroot =  Math.sqrt(discriminant);

        double root1 = (-b + sqroot) / 2.0;
        double root2 = (-b - sqroot) / 2.0;

        System.out.println(root1);
        System.out.println(root2);
    }
}