HT1541 i still cant get my code

Question

i still can't get my code

Answer 1

Exception in thread "main"
java.lang.NullPointerException
     at Board.pcomp(Board.java:81)
     at Board.addremovebridge(Board.java:34)
     at Twixt.main(Twixt.java:21)
So the null pointer occurs on the 81st line in the Board.java source code file. I'm not sure, but I expect this is line 81.if(d.x == e.x && d.y == e.y){Here's one way to troubleshoot null pointer problems. First find the line causing the error. Then, use System.out.println() statements to display the values of all the reference variables in that line, one variable at a time. So if I guessed correctly on line 81, you would put these statements just before line 81System.out.println("d " + d);
System.out.println("e " + e);Because d and e are the only reference variables in that line. When you run the code after putting these lines in, one or both of these will display "null" and that will tell you which variable to trace. You will need to trace backward through your code a find out why d or e or both are null.
(hint: A statement like Object[] objects = new Object[10];" creates an Object array with 10 elements, each of which is null. You have to use "objects[1] = new Object();" to create an element in the array which is an Object.)