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For example, to have a derived class with an overloaded function taking a double or an int, using the function taking an int from the base class, in C++, one would write: class B { public : void F ( int i ); }; class D : public B { public : using B :: F ; void F ( double d ); };
C++ does not have the keyword super that a subclass can use in Java to invoke the superclass version of a method that it wants to override. Instead, the name of the parent or base class is used followed by the scope resolution operator. For example, the following code presents two classes, the base class Rectangle, and the derived class Box.
The previous section notwithstanding, there are other ways in which ad hoc polymorphism can work out. Consider for example the Smalltalk language. In Smalltalk, the overloading is done at run time, as the methods ("function implementation") for each overloaded message ("overloaded function") are resolved when they are about to be executed.
When a class template like equal_comparable is instantiated, the in-class friend definitions produce nontemplate (and nonmember) functions (operator functions, in this case). At the time the idiom was introduced (1994), the C++ language did not define a partial ordering for overloaded function templates and, as a result, overloading function ...
Like with the previous examples, in the last example operator overloading is done within the class. In C++, after overloading the less-than operator (<), standard sorting functions can be used to sort some classes.
Often the compiler selects the overload to call based on the type of the input arguments or it fails if the input arguments do not select an overload. Older and weakly-typed languages generally do not support overloading. Here is an example of overloading in C++, two functions Area that accept different types:
All logical operators exist in C and C++ and can be overloaded in C++, albeit the overloading of the logical AND and logical OR is discouraged, because as overloaded operators they behave as ordinary function calls, which means that both of their operands are evaluated, so they lose their well-used and expected short-circuit evaluation property ...
An example would be a static method to sum the values of all the variables of every instance of a class. For example, if there were a Product class it might have a static method to compute the average price of all products. A static method can be invoked even if no instances of the class exist yet.