//  Scott DeRuiter     7/1/2002
//  Line.java
//  A Line class to be used by other programs.

public class Line   
{

	//  Data members for a line.
	private double x1, y1, x2, y2;

	//  A constructor that takes two ordered pairs.
	public Line ( double firstx, double firsty, double secondx, double secondy )   
	{
		x1 = firstx;
		y1 = firsty;
		x2 = secondx;
		y2 = secondy;
	}

	//  A constructor for default line, y = x
	public Line ( )   
	{
		x1 = 0.0;
		y1 = 0.0;
		x2 = 1.0;
		y2 = 1.0;
	}

	//  This is a method to find the slope.
	public double Slope ( )  
	{
		return ( ( y2 - y1 ) / ( x2 - x1 ) );
	}

	//  A method to find the y-intercept.
	public double Yint ( )   
	{
		return ( y1 - ( ( y2 - y1 ) / ( x2 - x1 ) ) * x1 );
	}

	//  This method prints the equation of the line using the previous two methods.
	public void PrintLine ( )   
	{
		System.out.print ( "y = " + Format.right ( Slope ( ), 8, 3 ) );
		System.out.println ( "x + " + Format.right ( Yint ( ), 8, 3 ) );
	}
}

//  Scott DeRuiter    7/1/2002
//  LineClient.java
//  Uses the Line class to get and print info about a line.
//  7/15/2011 - Greenstein: Changed TextReader to Scanner

import java.util.Scanner;

public class LineClient   
{
	public static void main ( String [] args )   
	{

		double xone, yone, xtwo, ytwo;
		Scanner keyboard = new Scanner ( );
		
		System.out.print ( "Enter x1:  " );
		xone = keyboard.nextDouble ( );
		System.out.print ( "Enter y1:  " );
		yone = keyboard.nextDouble ( );	
		System.out.print ( "Enter x2:  " );
		xtwo = keyboard.nextDouble ( );	
		System.out.print ( "Enter y2:  " );
		ytwo = keyboard.nextDouble ( );			

		Line myline = new Line ( xone, yone, xtwo, ytwo );
		myline.PrintLine ( );

		Line myline2 = new Line ( );
		myline2.PrintLine ( );
	}
}