Definition

C++’s standard template library(STL) ☜• Containers, iterators, algorithms (sort, find, etc.), numerics

A container is an object that stores (in memory) a collection of other objects (elements)

• implemented as class templates, so hugely flexible
• Read more info in C++ Primer 9.2 and 11.2

Cons for Containers:

• STL containers store by value, not by reference
  • When you insert an object, the container makes a copy
  • If the container needs to rearrange objects, it makes copies
    • e.g. if you sort a vector, it will make many, many copies
    • e.g. if you insert into a map, that may trigger every copies
  • You can insert a wrapper object with a pointer to the object

STL iterator

Each container class has an associated iterator class used to iterate through elements of the containers

• Iterator range is from begin up to end
  • end is one past the last container element

auto keyword is also very useful in this case:

STL list

• A generic doubly-linked list
  • Elements are not stored in contiguous memory locations
    • does not support random access (like list[5])
  • Some operations are much more efficient than vectors
    • Constant time insertion, deletion anywhere in list
    • can iterate forward or backwards
  • Has a built-in sort member function
    • doesn’t copy! manipulates list structure instead of element values