Thread: Integer and if statement

I am trying to determine if the user did not input a correct value without throwing an exception.

I have a String variable, done, which stores the user input and then if it is not storing "done" then it coverts the String into Integer. I got that part.

The question is, how do I determine that what is stored in done is not equal to an integer?

do
{
	if(done != null)
		if(Integer.parseInt(done).equals(Integer)
			list.add(Integer.parseInt(done));
	done = scan.nextLine();
}
 
while(!done.equalsIgnoreCase("done"));

I know thats wrong but it gives you the idea of what i want. anyway to do this?

BTW, list is an ArrayList<Integer>

You can't call a method on a primitive, and the compiler should be complaining to you about this. You would do your parsing in a try/catch block and catch for a NumberFormatException. Search on this as there are a lot of examples to be found.

A better way is to use Scanner's ability to know if the next token is an int or not.

This is what I changed it to and it worked:

do
{
	if(done != null)
		list.add(Integer.parseInt(done));
	if(scan.hasNextInt() || scan.hasNext("done"))
		done = scan.nextLine();
	else
		scan.nextLine();
}
 
while(done == null || !done.equalsIgnoreCase("done"));

Myself, I'd prefer doing something like (in pseudocode):

do
   prompt for an int
   if no int held by Scanner (! hasNextInt)
     done gets the Scanner's next line
   else
     list get's the Scanner's next int
     call nextLine() on Scanner to swallow end of line token
while done doesn't hold "done"