Question

As the title.
I tested NSScanner, but it passed some strange strings. (ex :123aaa).
Is there any way to convert string<->number strictly?

Answer 1

You can easily roll your own. Test whether the entire string was scanned, or whether there are additional characters.

NSScanner *scanner = [NSScanner localizedScannerWithString:str];
int i;
if (![scanner scanInt:&i] || [scanner scanLocation] < [str length]) {
    // str contains additional characters
    ...
} else {
    // str contains only an int
    ...
}