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Thread: Slopes/ Equations of a Line extended Code

  1. #1
    Junior Member Eoing008's Avatar
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    Question Slopes/ Equations of a Line extended Code

    Hi, need some help with this one. All I was asked was to find out if the three points are on the same line. I think that works. But I decided to go a little farther and try getting the equations of the relevant lines. That is where I am going wrong. All that is written in the Eclipse ( my IDE) console is the slopes or what I think is the slopes! Can anyone help please? By the way, this is revision. But I am very rusty and have never been a "Ace" programmer. Something I am trying to fix. Thanks in advance for any help given.


    import java.util.*;
    public class SameStraightLine
    {
    	public static void main(String[] args)
    	{
    		Scanner input= new Scanner(System.in);
    		int x1,y1,x2,y2,x3,y3,m1,m2,m3,l1,l2,l3;
    		int x= 120;char X = (char)x;
    		int y=121; char Y= (char)y;
    		Boolean SameLine= true;
    		System.out.println("Please enter the x1 co-ordinate: ");
    		x1=input.nextInt();
     
    		System.out.println("Please enter the y1 co-ordinate: ");
    		y1=input.nextInt();
     
    		System.out.println("Please enter the x2 co-ordinate: ");
    		x2=input.nextInt();
     
    		System.out.println("Please enter the y2 co-ordinate: ");
    		y2=input.nextInt();	
     
    		System.out.println("Please enter the x3 co-ordinate: ");
    		x3=input.nextInt();
     
    		System.out.println("Please enter the y3 co-ordinate: ");
    		y3=input.nextInt();
     
    		m1=((y2-y1)/(x2-x1));
    		m2=((y3-y2)/(x3-x2));
    		m3=((y1-y3)/(x1-x3));
     
    		l1=(y-y1-(m1*(x-x1)));
    		l2=(y-y2-(m2*(x-x2)));
    		l3=(y-y3-(m3*(x-x3)));
     
    		System.out.println("The equation of the line l1 is: "+l1);
     
    		System.out.println("The equation of the line l2 is: "+l2);
     
    		System.out.println("The equation of the line l3 is: "+l3);
     
     
    		if (l1==l2 && l2==l3)
    		{
    			System.out.println("It is "+SameLine+" that they lie on the same line");
     
    		}
    		else
     
    		{
    			System.out.println("It is "+(!SameLine)+" that they lie on the same line");
     
    		}
    	}
    }
    Last edited by jps; December 6th, 2012 at 04:25 AM. Reason: fixed code tag


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Slopes/ Equations of a Line extended Code

    Can you post the program's output and explain what is wrong with it and show what it should be?
    Also provide all the input required to execute the program. A very easy way to do that is by putting a String in the Scanner class's constructor:
    Scanner input= new Scanner("1\n33\n5\n44\n4\n");

    Can you make a line of code like the above with all the test data for the program to make for easier testing and to be sure the correct data is entered.
    If you don't understand my answer, don't ignore it, ask a question.

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