// ITI1120 (Fall 2012), Lab 3, Exercice 4
// Name: Grace Hopper, Student Number: 1234567
// Description: Program For Computing Number of Real Roots of a 
// quadratic equation 

import java.util.Scanner ;

class Lab3Ex4 
{
  /**
   * Given three coefficients of a quadratic equation,
   * computes number of real roots of the given equation
   */
  public static void main (String[] args)
  { 
    //Configuration for obtaining keyboard input
    //You can delete these lines if you use
    //the class IIT1120 to make the entry
    Scanner keyboard = new Scanner(System.in); 
    // Declaration variable to read inputs into
    double a, b, c;  // The coefficients
    int numberRoots; // Number of Reals
    // Print Identification information
    System.out.println();
    System.out.println("ITI1120 (F-2012), Lab 3, Exercice 4");
    System.out.println("Name: Grace Hopper, Student #: 1234567");
    System.out.println("Assistant to the teaching")  ;    
    System.out.println();
    // Read The Input Values
    System.out.println("Give the values of the coefficients a, b, and c.");
    a = keyboard.nextDouble();
    b = keyboard.nextDouble();
    c = keyboard.nextDouble();
    // Call to the method of solve the problem
    numberRoots = howManyRoots(a, b, c);
    // Display results to the screen
    System.out.println("The number of real roots for the equation is "+numberRoots);
  }
  
  /**
   * Description: Determines the number of roots of a quadratic
   * equation.
   * Parameters (Input): a, b, c - Coefficients of equation   
   **/
  public static int howManyRoots(double a, double b, double c)
  {
    // Declaration of variable for result
    int nbrR;  // A REAL NUMBER
    nbrR = 0; 
    // Declaration of intermediate variables
    double discriminant;  // b*b - 4*a*c
    // Calculate discriminant
    discriminant = Math.pow(b,2) - 4*a*c;
    if(discriminant < 0.0)
    {
      nbrR = 0;
    }
    else
    {
      if(discriminant > 0.0)
      {
        nbrR = 2;
      }
      else
      {
        nbrR = 1;
      }
    }
    // Return the result
    return(nbrR);
  }
}