APCS2012_C5X1_Quad.java

//Quad.java MrG 2012.1024
public class Quad
{
    private double a;
    private double b;
    private double c;

    /**
    Constructor
    @param a the coefficient of x^2
    @param b the coefficient of x^1
    @param c the coefficient of x^0
    */
    public Quad(double a, double b, double c)
    {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    /**
    Accessor
    @return the Discriminant
    */
    public double disc()
    {
        return b*b-4*a*c;
    }

    /**
    Accessor
    preCondition: disc()>=0
    @return first Real root
    */
    public double root1()
    {
        return (-b+Math.sqrt(disc()))/(2*a);
    }

    /**
    Accessor
    preCondition: disc()>=0
    @return second Real root
    */
    public double root2()
    {
        return (-b-Math.sqrt(disc()))/(2*a);
    }

    /**
    Accessor
    preCondition: disc()<0
    @return coefficient of real part of Complex root
    */
    public double real()
    {
        return -b/(2*a);
    }

    /**
    Accessor
    preCondition: disc()<0
    @return coefficient of imaginary part of Complex root
    */
    public double imag()
    {
        return Math.sqrt(Math.abs(disc()))/(2*a);
    }
}