title: How to subtract the int values within 2 UITextFields
body: <p>I have a IBAction UILabel to add a number every time it is pressed. I have a Total UITextField that a adds all 3 UILabels. Getting the total seems to be fine until I hit the subtract(buttonTap2) UILabel button.
  Here is an example of  the IBAction UILabel code not working:</p>
  
  <pre><code>- (IBAction)buttonTap2:(id)sender {
      int value = [currentLabel.text intValue] - 1;
      currentLabel.text = [NSString stringWithFormat:@"%d",value];
  
      int n1 = [label2.text intValue]; // total labels
      int n2 = [label3.text intValue];
      int n3 = [label4.text intValue];
      int s = n1 - n2 - n3;
      NSString *sn = [NSString stringWithFormat:@"%d",s];
      [tex7 setText:sn];
  </code></pre>