Int decimal count in iPhone - iphone

Question

I need to know whatever an int64_t has decimals, and how many. This should be placed in if-else-statement. I tried this code, but it causes the app to crash.
NSNumber *numValue = [NSNumber numberWithInt:testAnswer];
NSString *string = [numValue stringValue];
NSArray *stringComps = [string componentsSeparatedByString:#"."];
int64_t numberOfDecimalPlaces = [[stringComps objectAtIndex:1] length];
if (numberOfDecimalPlaces == 0) {
[self doSomething];
} else {
[self doSomethingElse];
}

Answer 1

Your question doesn't make a lot of sense; you are creating the NSNumber object from an int so it will never have decimal places, as an int cannot store them. The reason your code is crashing is that it assumes that the array of components is always at least 2 elements long (as you use objectAtIndex:1).
This is better, though still not that good:
NSString *answer = ...; // From somewhere
NSArray *stringComps = [answer componentsSeparatedByString:#"."];
if ([stringComps count] == 0) {
[self doSomething];
} else if [stringComps count] == 1) {
[self doSomethingElse];
} else {
// Error! More than one period entered
}
This still isn't a very good test as it only tests if a period (.) has been entered, not a valid number.