Modified Quad.java

 import java.util.Scanner;
class Complex
{
	private float real;
	private float imaginary;
	public void display()
	{
		if(imaginary > 0)
			System.out.println(real + "+" + imaginary + "i");
		else
			System.out.println(real + "-" + -imaginary + "i");
	}
	public float getReal()
	{
		return real;
	}
	public float getImaginary()
	{
		return imaginary;
	}
	public void setReal(float real)
	{
		this.real =  real;
	}
	public void setImaginary(float imaginary)
	{
		this.imaginary = imaginary;
	}
}
public class Quad {
	public static void main(String[] args)
	{
		float a,b,c;
		Scanner keyboard = new Scanner(System.in);
		System.out.println("Enter the coefficients of x^2,x^1, x^0: ");
		a = keyboard.nextFloat();
		b = keyboard.nextFloat();
		c = keyboard.nextFloat();
		keyboard.close();
		double discriminant = b*b - 4*a*c;
		if(discriminant < 0)
		{
			float real = -b/(2*a);
			float imaginary = (float) Math.sqrt(-discriminant)/(2*a);
			Complex root1 = new Complex();
			Complex root2 = new Complex();
			System.out.println("The roots are complex:");
			root1.setReal(real);
			root1.setImaginary(imaginary);
			root1.display();
			root2.setReal(real);
			root2.setImaginary(-imaginary);
			root2.display();
		}
		else if(discriminant > 0)
		{
			float root1 = (float) (-b+Math.sqrt(discriminant))/(2*a);
			float root2 = (float) (-b-Math.sqrt(discriminant))/(2*a);
			System.out.println("The roots are real and unequal: " + root1 + " " + root2);
		}
		else if(discriminant > 0)
		{
			float root1 = (float) (-b+Math.sqrt(discriminant))/(2*a);
			System.out.println("The roots are real and equal: " + root1 + " " + root1);
		}
	}
}