How do I end this program?

I need it to end up like this this below. I need it to end at the width or the height being 0. What can I do to make this happen?

Code:

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First corner X coordinate:

100

First corner Y coordinate:

100

Second corner X coordinate:

100

Second corner Y coordinate

100

Width:  0  Height: 0  Area: 0



finished

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Code:

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import java.util.Scanner;

class areasofrectangles

{

public static void main (String[] args )

{

Scanner scan=new Scanner( System.in );
int a, b, c, d;
int area, height, width;

System.out.print ("First corner X coordinate: ");
a = scan.nextInt ();

while (!( a ==0))

{

System.out.print ("First corner Y coordinate: ");
b = scan.nextInt ();


System.out.print ("Second corner X coordinate: ");
c = scan.nextInt ();

System.out.print ("Second corner Y coordinate: ");
d = scan.nextInt ();

width = Math.abs(c - a);

height = Math.abs(d - b);

area = width * height;

System.out.println ("Width: " + width + " Height: " + height + " Area: " + area);

System.out.println ();

System.out.print ("First X Coordinate: ");

a = scan.nextInt ();

}

System.out.println ("Finished");

}
}

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