Objective-C classification

By classification, you can add new methods to existing classes without the need for source code. This is a bit like the Extension Method in C.

In this case, an example is provided to convert a string into a camper type and remove spaces.

Nsstring + camelcase. h

 
# Import <Foundation/Foundation. h> // nsstring indicates the name of the class to be added. The class must already exist. // Camelcase is the name of the category added for the class. // You can only add methods, but not variables. // Naming convention for header files: classname + categoryname. h @ interface nsstring (camelcase)-(nsstring *) camelcasestring; @ end
 

Nsstring + camelcase. m

# Import "nsstring + camelcase. H" @ implementation nsstring (camelcase)-(nsstring *) camelcasestring {// call the internal method of nsstring to obtain the hump string. // Self points to the class of the added category. Nsstring * castr = [self capitalizedstring]; // creates an array to filter out spaces and combines characters using separators. Nsarray * array = [castr componentsseparatedbycharactersinset: [nscharacterset whitespacecharacterset]; // output nsstring * output = @ ""; for (nsstring * word in array) {output = [Output stringbyappendingstring: Word];} return output ;}@ end
 

Main. m

#import 
  
    # import "nsstring + camelcase. H "int main (INT argc, const char * argv []) {ngutoreleasepool * Pool = [[ngutoreleasepool alloc] init]; nsstring * STR = @" My name is Bill. "; nslog (@" % @ ", STR); STR = [STR camelcasestring]; nslog (@" % @ ", STR); [pool drain]; return 0 ;}