Question

I was wondering how it is possible to validate input from a UITextField in a case such as this:

NSString *str = [UItextfield1 text];
long long value = [str longLongValue];

How do I check first if the number won’t wrap around, and if it is numeric before passing it on?

Answer 1

Don’t check first, check after. The docs for longLongValue say that if the string can’t be converted, value will be 0. If its magnitude would be too great, you’ll get LLONG_MAX or LLONG_MIN