returning index array objective c

Answer 1

You can use NSArray's indexOfObjectIndenticalTo: method:

if([appDelegate.exerciseReference containsObject:aExerciseRef.IDE])
{
    return [appDelegate.exerciseReference indexOfObjectIdenticalTo:aExerciseRef.IDE];
}

It returns an NSUInteger (a typedef for an int or long for 32-bit or 64-bit applications respectively) of the lowest index where the object is located.