Standard template library in C++ is a collection of containers, binders, allocators, predicates, negators, adaptors, iterators, stacks, lists, comparison functions, function objects, queues, vectors, algorithms, and routines.
Allocator: Allocator is used for controlling memory allocation in a container. A default allocator can be used or a custom one can be defined.
Adaptor: Adaptor is used to transform one element to another.
Comparison functions: A comparison function is used to compare two elements in a container.