CS193P Assignment 1 Clear

Question

I just started the Stanford iOS5 class and have completed the RPN calculator, but want to make the "Clear" button work a little differently. This is how I have it now, with no changes to the CalculatorModel "brain":

- (IBAction)clearPressed
{
    self.display.text = @"";                        // Clear the display
    self.historyWindow.text = @"";                  // Clear the history window
    self.model = nil;                               // Reset the stack
    self.userIsInMiddleOfEnteringNumber = NO;       // Reset user typing boolean
}

I may be wrong, but "self.model = nil;" seems like it doesn't really remove the objects from the stack, it kind of just imitates that. So I added a function to the CalculatorModel "brain":

-(void) clearOperandStack
{
    [self.operandStack removeAllObjects];
}

and want to call it in my "clearPressed" function in the CalculatorViewController but I am having issues possibly because I do not fully understand objective c yet. This is what I thought I had to do, but it does not seem to want to work.

- (IBAction)clearPressed
{
    self.display.text = @"";                        // Clear the display
    self.historyWindow.text = @"";                  // Clear the history window
//    self.model = nil;                               // Reset the stack
    [self.model clearOperandStack];
    self.userIsInMiddleOfEnteringNumber = NO;       // Reset user typing boolean
}

Can someone please explain to me the proper way to call that method / what I am doing wrong?

Answer 1

My solution of assignment 1: https://github.com/rl1987/CS193p-Homework-1