Q: How can I write a method that takes a variable number of arguments, like NSString's +stringWithFormat:?
A: Methods that take variable arguments are known as variadic methods.Keep in mind that the implementation of an Objective-C method is just a block of code, like a C function. The variadic argument macros described in the stdarg(3) manual page work the same way in a method as they do in an ordinary function.
Mac Developer Library
#import <Cocoa/Cocoa.h> @interface NSMutableArray (variadicMethodExample) - (void) appendObjects:(id) firstObject, ...; // This method takes a nil-terminated list of objects. @end @implementation NSMutableArray (variadicMethodExample) - (void) appendObjects:(id) firstObject, ... { id eachObject; va_list argumentList; if (firstObject) // The first argument isn't part of the varargs list, { // so we'll handle it separately. [self addObject: firstObject]; va_start(argumentList, firstObject); // Start scanning for arguments after firstObject. while (eachObject = va_arg(argumentList, id)) // As many times as we can get an argument of type "id" [self addObject: eachObject]; // that isn't nil, add it to self's contents. va_end(argumentList); } } @end
