Question

im trying this:

    NSNumber *num1;
    NSNumber *num2;
    self.addNumberOfRoundsText.text = [num1 stringValue];
    self.numberOfRoundsText.text = [num2 stringValue];
    NSNumber *sum = [NSNumber numberWithInt:([num1 intValue] + [num2 intValue])];
    NSLog(@"%@", [sum stringValue]);

For some reason, the console keeps outputting 0 im not sure if there is something i am missing. I just want to get the text from two UITextField’s and add them. Then output them to the console. Thank you for the help!

Answer 1

In your example code, you haven’t initialized num1 and num2. So (if you are using ARC, which is the default for new projects), those variables are initialized to nil.

In Objective-C, you can send any message (like stringValue or intValue) to nil, and it will return 0 or nil back. So:

NSNumber *num1; // initialized to nil by ARC
NSNumber *num2; // initialized to nil by ARC

// This sets self.addNumberOfRoundsText.text to nil.
self.addNumberOfRoundsText.text = [num1 stringValue];

// This sets self.numberOfRoundsText.text to nil.
self.numberOfRoundsText.text = [num2 stringValue];

// This gets 0 for [num1 intValue] and 0 for [num2 intValue], which add up
// to 0, so sum is an NSNumber representing zero.
NSNumber *sum = [NSNumber numberWithInt:([num1 intValue] + [num2 intValue])];
NSLog(@"%@", [sum stringValue]);

I’m not sure what you’re actually trying to do. Maybe you have two text fields, and each text field contains a number, and you want to add up those two numbers. If that’s what you want to do, try this:

int n1 = self.addNumberOfRoundsText.text.intValue;
int n2 = self.numberOfRoundsText.text.intValue;
int sum = n1 + n2;
NSLog(@"sum = %d", sum);