Question

Hey guys I’m trying to make a basic calculator (polish style) but can’t figure out why my code to stop double decimal entry won’t work. I found a different way on another thread, but I want to understand why my code won’t work. I’m using an nsRange to search the already entered digits in the label for a decimal, then a second conditional to see if the digit to be appended is a decimal Please help..

- (IBAction)digitPressed:(UIButton *)sender 
{
    NSString *digit = [sender currentTitle];  // the number on the button pressed


    NSString *decimalErrorChecker = [[self display] text];  //search line for .
    NSRange range = [decimalErrorChecker rangeOfString:@"."];



    if ((range.location != NSNotFound) && ((digit == @"."))) {  //double if to stop 2nd 
           //SHOW ERROR


    }else  //APPEND DIGIT TO ALREADY ENTERED String.

Answer 1

Compare NSString using isEqualToString, not ==:

if ((range.location != NSNotFound) && [digit isEqualToString: @"."])