Exploring C++20: The Programmer's Introduction to C++

© Ray Lischner 2020

R. LischnerExploring C++20https://doi.org/10.1007/978-1-4842-5961-0_44

44. Function Objects

Ray Lischner¹ 

(1)

Ellicott City, MD, USA

 

Classes have many, many uses in C++ programs. This Exploration introduces one powerful use of classes to replace functions. This style of programming is especially useful with the standard algorithms.

The Function Call Operator

The first step is to take a look at an unusual “operator,” the function call operator, which lets an object behave as a function. Overload this operator the same way you would any other. Its name is operator(). It takes any number of parameters and can have any return type. Listing 44-1 shows another iteration of the generate_id class (last seen in Listing 41-5), this time ...