Removing a value from an array

Question

I have searched the forums, and found many post about this, but with different variances.
i have an array, where if a user passes an argument that already exists in the array, it will remove that value from the array. when i run the code below i get a boolean exception. i "think" my thinking is correct, but i cannot seem to put it into code terms (HAH! thats a first eh?).
what exactly be the difference to setting the position to 0 or to null?
public void remove(int lessNum) throws NotFoundException {
   for( int i=0;i<this.occupied.length;i++) {
        if(occupied.equals(lessNum)
     occupied[i] = null;
     else
     throw new NotFoundException();
}//end for
}//end remove
this is the exception i get: boolean cannot be dereferenced
                    if(occupied[i].equals(lessNum)
^
Thanks,
J

Answer 1

Hi.
(You have a few typos in your code, but I'm assuming that's because you typed it in again when you sent your posting rather than copying and pasting it. Your compilation error is also not consistent with the code, but I'll take a guess at what is going on)
There are a number of things that are strange about the code example.
1. It looks like your 'occupied' field is a boolean[] (the compilation error indicates that this is the case). That means each element of occupied is a primitive boolean, not a reference. Therefore trying to dereference it makes no sense. This is what the compiler error is telling you. Note that this is not an exception.
2. Now looking at the intent of what I think you're trying to do... I think you are trying to determine if element i of the 'occupied' array is equal to the parameter 'lessNum'. This is nonsensical since the elements of 'occupied' are booleans and lessNum is an int.
3. Finally, trying to set an element of 'occupied' to null, doesn't make sense because the elements of 'occupied' are not references, but primitives.
Regarding your question about the difference between setting something to 0 or null: I assume you come from a C or C++ background where 0 and null are the same thing. In Java, null is not equivalent to 0 but is instead a special value for a variable of reference type that means that the variable is not currently referring to anything. In C and C++ if a pointer has the value 'null' or 'zero' it simply means that any attempt to dereference it will mean an attempt to look for an object at memory address 0 which will usually result in unimaginable horrors (alright, it's not that bad).
Regards,
Lance
Lance Walton - [email protected]
Team In A Box - Software without Tragedy
http://www.teaminabox.co.uk