argument isKindOfClass: [NSNumber class] - sane way to check this? - objective-c

Question

So I was playing with something where the class type of the arg is unknown until runtime.
like this:
- (NSNumber *)doWhatever:(id)arg
{
// this ALWAYS FAILS
if ([arg isKindOfClass:[NSNumber class]]) {
return arg;
}
else {
// what was it???
NSLog("arg klass=%#", [arg class]); // prints NSCFNumber
}
// This check works correctly.
if ([arg isKindOfClass:[NSArray class]]) {
for (id x in arg) {
NSNumber *result = [self doWhatever:x];
if (result) {
return result;
}
}
}
return nil;
}
- (void)someMethod
{
NSArray *myArray = [NSArray arrayFromObjects:[NSNumber numberWithInt:3], nil]];
NSNumber *myNum = [self doWhatever:myArray];
NSLog(#"myNum=%#", myNum);
}
This is obviously a contrived example of what I'm trying to do.
The point is this never works b/c the class of "arg" always appears as NSCFNumber, and I can't figure out a way to check for that.
Any way to make it less confusing to detect whether an arbitrary value in an array is an integer or not?
UPDATE:
Thanks #chuck, #omz, and #Nikita Leonov for your help. What I posted here originally was just a simplification of the problem I was having and wrote it here without running it first. That code once updated to remove the errors (see below) runs fine actually.
The mistake I made in my real code that I was having trouble with was equally silly--I was passing the array back in to "doWhatever" instead of the item at array's index, which is why I was having problems.
Thanks for trying to help, however misguided my question was.
Sorry for wasting everybody's time!
Corrected code that runs as desired:
- (NSNumber *)doWhatever:(id)arg
{
// this NOW WORKS
if ([arg isKindOfClass:[NSNumber class]]) {
return arg;
}
else {
// what was it???
NSLog(#"arg klass=%#", [arg class]); // prints NSCFNumber
}
// This check works correctly.
if ([arg isKindOfClass:[NSArray class]]) {
for (id x in arg) {
NSNumber *result = [self doWhatever:x];
if (result) {
return result;
}
}
}
return nil;
}
- (void)someMethod
{
NSArray *myArray = [NSArray arrayWithObjects:
[NSNumber numberWithInt:1],
[NSNumber numberWithInt:2],
[NSNumber numberWithInt:3],
[NSNumber numberWithInt:4],
nil];
NSNumber *myNum = [self doWhatever:myArray];
NSLog(#"myNum=%#", myNum);
}

Answer 1

NSCFNumber is a subclass of NSNumber. As long as you're using isKindOfClass: rather than isMemberOfClass: or [arg class] == [NSNumber class], it should work. If not, your problem is elsewhere.