Messaging is the terminology for invoking methods on an object. The format for a message expression is as follows (the brackets are required):
or in Objective-C parlance
// Create an instance of SomeClass object
SomeClass *ptr = [[SomeClass alloc] init];
// Send the message 'printInstanceVars' to the 'ptr' receiver
If we want to pass an argument as part of the message (that is, pass a parameter to the method), we send a message that looks like this:
For example, assume setStr and setX are two methods in the SomeClass object and ptr is a pointer an instance of SomeClass . Here is how we might pass arguments to each method.
Side note: The @ symbol at the front of @”Testing” string is convenience method that converts the given string to an NSString object, which in the case of the setStr method, is the required type for the parameter.