NSString intValue not working for retrieving phone number

Question

I have a phone number formatted as an easy to read phone number, i.e., (123) 123-4567

However, when I want to use that phone number in code, I need to parse that string into a number variable (such as an int)

However, [string intValue]; doesn't work - I've used intValue about a million times in previous projects, all with no problem, however here, every string I pass in, I get the same, random int back out:

- (int)processPhoneNumber:(NSString *)phoneNumber {
      NSMutableString *strippedString = [NSMutableString stringWithCapacity:10];

      for (int i=0; i<[phoneNumber length]; i++) {
           if (isdigit([phoneNumber characterAtIndex:i])) {
                  [strippedString appendFormat:@"%c",[phoneNumber characterAtIndex:i]];
           }
      }

     NSLog(@"clean string-- %@", strippedString);

     int phoneNumberInt = [strippedString intValue];

     NSLog(@"**** %d\n &i", phoneNumberInt, phoneNumberInt);

     return phoneNumberInt;
}

Then when I call this method:

NSLog(@"%i", [self processPhoneNumber:self.phoneNumberTextField.text]);

I get: 2147483647. Every input I give this method returns: 2147483647

I suggest that you're on entirely the wrong track. A phone "number" isn't really a number. It doesn't represent a _quantity_. You would never perform arithmetic on one. It's actually a string of digits, and you should handle it that way. See [What's the right way to represent phone numbers?](http://stackoverflow.com/questions/3483156/whats-the-right-way-to-represent-phone-numbers) — jscs, Oct 21 '12 at 19:28
I'm 100% with @Josh Caswell here. In your int representation, you can't even tell if you need to call some "0" at the beginning! — Eiko, Oct 21 '12 at 19:30
Did you step through your code using the Xcode debugging tools to find out where the problem arises? Knowing which part of your code doesn't work properly would help a lot. — Tim Vermeulen, Oct 21 '12 at 19:31
That makes sense and I agree. I made it an int so I could easily call it, but your explanation makes more sense. If you make that into an answer, I'll accept it — Andrew, Oct 21 '12 at 19:31

score 5 · Accepted Answer · edited May 23 '17 at 12:06

As CRD has already explained, you're trying to convert that string to a type that's too small to hold the value, and you're getting back the maximum possible value for that type.

Your real problem is deeper, however. A phone "number" isn't really a number. It doesn't represent a quantity. You would never perform arithmetic on one. It's actually a string of digits, and you should handle it that way. Don't convert it; just operate on the string.

See also What's the right way to represent phone numbers?

score 4 · Answer 2 · answered Oct 21 '12 at 19:25

4

2147483647 is INT_MAX which is returned on overflow. How large is your phone number, will it fit into an int? Maybe you should use longLongValue?

answered Oct 21 '12 at 19:25

CRD

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my phone numbers are 10 digits - as it that overflow value. but say the area code is 803, would that mean a number thats 10 digits long, starting with 803 would overflow? – Andrew Oct 21 '12 at 19:28
@Andrew - yes it will overflow. Your `int` is 32-bit signed. Use `long long` (or `UInt64` etc.) to get a 64-bit unsigned value. – CRD Oct 21 '12 at 19:31
Thanks. I've never really understood the difference between int, long, short, signed, unsigned, etc. – Andrew Oct 21 '12 at 19:32
@Andrew - On Mac OS X `int` is always 32 bits, `long long` is always 64 bits, and `long` depends on how you compile. And different systems use different models for 64-bit - see . – CRD Oct 21 '12 at 19:38

NSString intValue not working for retrieving phone number

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