Detecting if NSNumber is between 0 and 255

Question

I am trying to detect whether a NSNumber is between 0 and 255 or not. Whenever I run the app, I receive the alert view that my number is greater than 255, even when it is not. I do not have this problem with 0.

if (redValue < 0) {

    NSLog(@"Red value is less than 0");

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Your number must be greater than 0." message:nil delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];

    [alert show];
    [alert release];


} else if (redValue > 255) {

    NSLog(@"Red value is greater than 255");

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Your number must be less than 255." message:nil delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];

    [alert show];
    [alert release];

}

Additionally, I receive this warning on the "else if (redValue > 255)" line: Ordered comparison between pointed and integer ('NSNumber *' and 'int'), So I'm assuming I have to convert this NSNumber to an integer?

See this question for more about converting from NSNumber to int : http://stackoverflow.com/questions/3555906/how-to-convert-nsnumber-to-int-in-objective-c — Sam Holloway, Aug 21 '11 at 20:56

score 27 · Accepted Answer · answered Aug 21 '11 at 20:56

27

Should be:

if([redValue intValue] < 0) {
...

if([redValue intValue] > 255) {
...

Assuming it is an int. If it isn't go to the NSNumber Class Reference look under "Accessing Numeric Values" and replace intValue with the appropriate thing.

answered Aug 21 '11 at 20:56

Dair

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ennuikiller · Answer 2 · 2011-08-21T21:02:50.073

3

use intValue to get the number as an int:

[redValue intValue]

edited Aug 21 '11 at 21:02

answered Aug 21 '11 at 20:54

ennuikiller

46,381
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score 1 · Answer 3 · edited Feb 10 '13 at 22:34

1

if (redValue.intValue >255)
{
    // it's greater than 255
}

edited Feb 10 '13 at 22:34

Luke

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answered Aug 21 '11 at 20:55

Arvin Am

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11

score 1 · Answer 4 · edited Feb 10 '13 at 22:33

1

try this

[redValue intValue] > 255

edited Feb 10 '13 at 22:33

Luke

11,426
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69

answered Aug 21 '11 at 20:56

Andiih

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Detecting if NSNumber is between 0 and 255

4 Answers4