CppCon 2026

Choosing the right Standard Library container and using it correctly can have a profound impact on the performance of a program, but what may appear to be the obvious choice can turn out to be the wrong one. In this two-part series we will explore the abstractions each container models and the practical limitations it imposes. We will see that choosing between them requires an understanding not only of the speed and size tradeoffs of each container, but also of the difference between algorithmic complexity and actual behavior. Our goal will be to learn how to choose the right tool for the job and extract the best performance from it.

In Part 1 we will survey the containers and adaptors in the classic STL, including the additions introduced in C++11. Along the way we will investigate some premises underlying the original C++98 STL design that often lead to the wrong choice today.

In Part 2 we will examine a C++17 improvement to the associative containers and the powerful new containers and adaptors that C++23 and C++26 provide. We will finish with a discussion of a proposed future container that deliberately diverges from the original STL design principles while addressing several limitations of the current sequence containers.