Quadratic Formula Example in java.

Source:

class QuadraticFormula {
   public static void main(String[] args) {
 
      double a = 0;
      double b = 0;
      double c = 0;
      double discriminant = 0;
      double root1 = 0;
      double root2 = 0;
 
      if (args.length == 3) {
         a = Double.parseDouble(args[0]);
         b = Double.parseDouble(args[1]);
         c = Double.parseDouble(args[2]);
      } else {
         System.err.println("Wrong.");
      }
 
      discriminant = Math.pow(b,2) - 4*a*c; 
      root1 = (-b + Math.sqrt(discriminant))/(2*a); 
      root2 = (-b - Math.sqrt(discriminant))/(2*a); 
 
      System.out.println("Discriminant = " + discriminant);
 
      if(discriminant > 0) {
         System.out.println("Roots: " + root1  + ", " + root2);
      } 
 
      else if(discriminant == 0) {
         System.out.println("Only one root.");
         System.out.println("Root: " + root1);
      } 
 
      else {
         System.out.println("It has Complex Roots.");
         root1 = -b/(2*a);
         root2 = Math.sqrt(-discriminant)/(2*a);
         System.out.println("Roots: " + root1 + " + " + root2 + "i, " 
               + root1 + " - " + root2 + "i");
      }
   }
}

Output:

   # java QuadraticFormula 2 5 -3
   Discriminant = 49.0
   Roots: 0.5, -3.0

   # java QuadraticFormula 3 6 3
   Discriminant = 0.0
   Only one root.
   Root: -1.0

   # java QuadraticFormula 1 2 3
   Discriminant = -8.0
   It has Complex Roots.
   Roots: -1.0 + 1.4142135623730951i, -1.0 - 1.4142135623730951i