C++ High Performance

Using std::any as the base for a dynamic-size heterogenous container

Note that std::any was added in C++17; if your compiler does not include std::any, you can use boost::any from the Boost Library instead.

The simplest solution is to use std::any as the base type. The std::any object can store any type of value in it:

auto container = std::vector<std::any>{42, "hi", true}; 

It has some drawbacks, though; every time a value in it is accessed, the type must be tested for at runtime. In other words, we completely lose the type information of the stored value at compile time. Rather, we have to rely on runtime type checks for the information.

If we would like to iterate our container, we need to explicitly ask every std::any object if you are ...