package lab 2;
/**
 * @author wahl
 * A simple class for quadratic expressions of the form a*x^2 + b*x + c
 * (source code for lab 2, Algorithms, CS 225)
 *
 */

public class Quadratic 
{
	// data fields
	private double a;		// coefficient of x^2
	private double b;		// coefficient of x
	private double c;		// constant term
	
	/**
	 * 3-arg constructor
	 * Constructs the Quadratic object corresponding to a*x^2 + b*x + c
	 * @param a (double) -- the leading coefficient 
	 * @param b (double) -- the middle coefficient 
	 * @param c (double) -- the constant term 
	 */
	public Quadratic(double a, double b, double c)
	{
		// write 3 lines of code to implement
	}
	
	/**
	* converts this Quadratic to its String representation
	*/
	public String toString()
	{
		return a + "x^2 + " + b + "x + " + c;
	}
	
	/**
	* determines if this Quadratic has any real roots
	* @return true iff there are real roots
	*/
	public boolean hasRoots()
	{
		// a quadratic expression has real roots iff 
		// b*b - 4*a*c is non-negative 
		
		// write one or two lines of code to implement		
	}	
	
	/**
	 *  finds the real roots of this Quadratic object
	 * @return an array of doubles r[0..1] containing the real roots 
	 * of this Quadratic function.  If there are no real roots, both 
	 * entries in the returned array will have the value Float.Nan 
	 * ("not a number")
	 */
	public double[] roots()
	{
		// write code to declare & create array r
		
		// write code to calculate and store d = b*b - 4*a*c
		
		if(d < 0)	// no real roots
		{
			r[0] = Float.NaN; 	 // Float.NaN is a constant holding 
			r[1] = Float.NaN;		 // a “Not-a-Number” value 
		}
		
		else
		{
			// sq = square root of discriminant
			double sq = Math.sqrt(d);			

			// write code to store root #1 in r[0]
			// write code to store root #2 in r[1]
		}
		
		// write a return statement to finish this method
	}   

	// USE THE SOURCE MENU IN ECLIPSE TO AUTOMATICALLY GENERATE 
	// GETTERS AND SETTERS

	/**
	 * @return the a
	 */
	public double getA() {
		return a;
	}

	/**
	 * @param a the a to set
	 */
	public void setA(double a) {
		this.a = a;
	}

	/**
	 * @return the b
	 */
	public double getB() {
		return b;
	}

	/**
	 * @param b the b to set
	 */
	public void setB(double b) {
		this.b = b;
	}

	/**
	 * @return the c
	 */
	public double getC() {
		return c;
	}

	/**
	 * @param c the c to set
	 */
	public void setC(double c) {
		this.c = c;
	}
	
	/**
	 * main test method 
	 */
	public static void main(String[] args) 
	{
		// Create f(x) = x^2 - 5
		Quadratic f = 

		// Create g(x) = 0.005*x^2 + 10.8*x + 5.2
		Quadratic g 
		
		// Test the toString method
		System.out.println("f = " + f.toString());
		System.out.println("g = " + g.toString());
	
		// Find the roots of f and g
		double[] rootsF = 
		double[] rootsG = 

		// Report the roots of f and g
		System.out.print("The real roots of " + f.toString() + " are ");
		{
			if(!f.hasRoots())
				System.out.print("nonexistent\n");
			else
				System.out.println(rootsF[0] + " and " + rootsF[1]);
		}

		System.out.print("The real roots of " + g.toString() + " are ");
		{
			if(!g.hasRoots())
				System.out.print("nonexistent\n");
			else
				System.out.println(rootsG[0] + " and " + rootsG[1]);
		}	

		
	} // end main
} // end Quadratic 
3