Method overloading

In some programming languages, function overloading or method overloading is the ability to create multiple methods of the same name with different implementations. Calls to an overloaded function will run a specific implementation of that function appropriate to the context of the call, allowing one function call to perform different tasks depending on context.

For example, doTask() and doTask(object O) are overloaded methods. To call the latter, an object must be passed as a parameter, whereas the former does not require a parameter, and is called with an empty parameter field. A common error would be to assign a default value to the object in the second method, which would result in an ambiguous call error, as the compiler wouldn't know which of the two methods to use.

Another appropriate example would be a Print(object O) method. In this case one might like the method to be different when printing, for example, text or pictures. The two different methods may be overloaded as Print(text_object T); Print(image_object P). If we write the overloaded print methods for all objects our program will "print", we never have to worry about the type of the object, and the correct function call again, the call is always: Print(something).

It is a classification of static polymorphism in which a function call is resolved using the 'best match technique', i.e. the function is resolved depending upon the argument list. Method overloading is usually associated with statically-typed programming languages that enforce type checking in function calls. When overloading a method, you are really just making a number of different methods that happen to have the same name. The determination of which of these methods are used is resolved at compile time.

Method overloading should not be confused with forms of polymorphism where the correct method is chosen at runtime, e.g. through virtual functions, instead of statically.

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