Exceptional C++ Style 40 New Engineering Puzzles, Programming Problems, and Solutions

Chapter 4. Standard Library Member Functions

Difficulty: 5

Reuse is good, but can you always reuse the standard library with itself? Here is an example that might surprise you, where one feature of the standard library can be used portably with any of your code as much as you like, but it cannot be used portably with the standard library itself.

JG Question

1. What is std::mem_fun? When would you use it? Give an example.

Guru Question

1. Assuming a correct incantation in the indicated comment, is the following expression legal and portable C++? Why or why not?

   std::mem_fun</*…*/>(&(std::vector<int>::clear))
   

Solution

Fun with mem_fun

1. What is std::mem_fun? When would you use it? Give an example.

The standard mem_fun adapter lets you use member functions with ...