Comparing version numbers

Question

Some time ago, I read that comparing version numbers can be done using the following code snippet:

NSString *vesrion_1 = @\"1.2.1\";
NSString *version_2 = @\         


        

Answer 1

I don't know of anything built in that will do it, but I have heard that the Sparkle framework has a version comparator.

Browsing quickly through the source reveals that the SUStandardVersionComparator object seems to be in charge of it. It conforms to the protocol,which means you could probably just use it like this:

NSString *versionA = @"1.2.1";
NSString *versionB = @"1.2.0";
id  comparator = [SUStandardVersionComparator defaultComparator];
NSInteger result = [comparator compareVersion:versionA toVersion:versionB];
if (result == NSOrderedSame) {
  //versionA == versionB
} else if (result == NSOrderedAscending) {
  //versionA < versionB
} else {
  //versionA > versionB
}

(note: code untested and typed in a browser. Caveat Implementor)