Ad hoc polymorphism: Difference between revisions

Revision as of 22:09, 2 January 2022

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===Overloading===

To handle these six function calls, four different pieces of code are needed— (or ''three'', if strings are considered to be lists of characters):

* In the first case, [[integer (computer science)|integer]] addition must be invoked.

* In the second and third cases, [[floating point|floating-point]] addition must be invoked (with [[type promotion]], or [[type coercion]], in the third case).

* In the fourth and fifth cases, [[List (computing)|list]] [[concatenation]] must be invoked.

* In the last case, [[literal string|string]] concatenation must be invoked.

Thus, the name <code>+</code> actually refers to three or four completely different functions. This is an example of ''[[Overloading (programming)|overloading]]''.

(Note the ambiguity in the string types used in the last case. Consider <code>"123" + "456"</code> in which the programmer might ''naturally'' assume addition rather than concatenation. They may expect <code>"579"</code> instead of <code>"123456"</code>. Overloading can therefore provide different meaning, or semantics, for an operation, as well as differing implementations.)

==References==