Thread 1: Signal SIGABRT due to calling another method

Question

Sorry for this common error.

But I am creating a convertor application in X-Code 4.6

I am creating a binary to decimal converter and I want to be able to put two areas to do calculations on. But for some reason this is giving me a Signal abort issue.

I have tried searching for some answers, but I have learnt that this error is has a massive scope, so is there someone able to assist me, I am only beginner at iOS Programming.

Error:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[BinaryToDecimal calculation]: unrecognized selector sent to class 0x7c98'

The interface of the application contains 8 buttons so that the user can switch each button to a one or zero.

So the first code called is;

- (IBAction)chk1:(id)sender {
    if(chk1)
    {
        number = number + 1;

        [_chk1 setTitle:@"1" forState:UIControlStateNormal];
        chk1 = false;
    } else {
        number = number - 1;
        [_chk1 setTitle:@"0" forState:UIControlStateNormal];
        chk1 = true;
    }
    [[self class]calculation];
}

and calculation is

- (void)calculation {
    switch (operatorVar) {
        case 1:
            answer = number + number2;
            _output.text = [NSString stringWithFormat:@"%f", answer];
            break;
        case 2:
            answer = number - number2;
            _output.text = [NSString stringWithFormat:@"%f", answer];
            break;
        case 3:
            answer = number * number2;
            _output.text = [NSString stringWithFormat:@"%f", answer];
            break;
        case 4:
            answer = number / number2;
            _output.text = [NSString stringWithFormat:@"%f", answer];
            break;
        default:
            answer = number + number2;
            _output.text = [NSString stringWithFormat:@"%f", answer];
            break;
    }
}

Before I was doing that my code was

- (IBAction)chk1:(id)sender {
        if(chk1)
        {
            number = number + 1;

            [_chk1 setTitle:@"1" forState:UIControlStateNormal];
            chk1 = false;
        } else {
            number = number - 1;
            [_chk1 setTitle:@"0" forState:UIControlStateNormal];
            chk1 = true;
        }
        _output.text = [NSString stringWithFormat:@"%f", number];
    }

That code above worked fine, but When I called the calculation method, the signal abort error stopped the application from working.

Answer 1

According to the Error description you shared, you are calling method calculation as a Class method but your method calculation is a instance method. use [self calculation];

Answer 2

I Think problem is

[_chk1 setTitle:@"1" forState:UIControlStateNormal];

This statement

_chk1 is button object once crass check.

other wise use this statement for button Action method like this

better use the method like " -(IBAction)buttonTouched:(UIButton *)sender" and Maintain the naming convention for each object you have declare all object same for exe: method name , button object, bool value also don't write code like that ...........

• (IBAction)chk1:(UIButton*)sender {

  if(chk1) { number = number + 1;

      [sender setTitle:@"1" forState:UIControlStateNormal];
      chk1 = false;
  } else {
      number = number - 1;
      [sender setTitle:@"0" forState:UIControlStateNormal];
      chk1 = true;
  }
  _output.text = [NSString stringWithFormat:@"%f", number];
  

  }