How to check whether a char is digit or not in Objective-C?

Question

I need to check if a char is digit or not.

NSString *strTest=@\"Test55\";
char c =[strTest characterAtIndex:4];

I need to find out if \'c\' is

Answer 1

Note: The return value for characterAtIndex: is not a char, but a unichar. So casting like this can be dangerous...

An alternative code would be:

NSString *strTest = @"Test55";
unichar c = [strTest characterAtIndex:4];
NSCharacterSet *numericSet = [NSCharacterSet decimalDigitCharacterSet];
if ([numericSet characterIsMember:c]) {
    NSLog(@"Congrats, it is a number...");
}