Thread: Find first null in an array of objects

Hi!

I'm a java beginner and can´t figure out what´s wrong with my code.
The question is: How do I find the first null in an array of objects, arr[10], and then add an object, obj, to that index.

I can think of something like this:

for(int i = 0; i<10; i++)
{
        if(arr[i] == null)
        {
            arr[i] = obj;
            return i; //return statement because we are inside a int-method
        }
}

I can also think of something like "if (arr[i] != null) then do nothing, else do arr[i] = obj", but I think that´s an ugly solution.

Thankful for all kind of inputs

Hank

No, I´m at work. Do you se any direct problem with my solution. The "==" for example.

My teacher wrote:

// is it a free spot at index i? if(arr[i] != null) {
arr[i] = obj;

and I don't understand it. I thought that "if(arr[i] != null)" meant that if arr[i] is not null...

It looks fine. Although instead of a return statement, you could use break to break out of the loop and then return.

You can try:

for(int i = 0; i<10; i++)
{
        try{
                if(arr[i].length==0);        //if null, will throw exception
        }catch(Exception e){
                arr[i] = obj;
                break;
        }
}

It's ugly but it should work fine.