STL learning notes 0x0001 (container classification)

STL Six parts ：

         An algorithm is like an operation , The contents of the operation are contained in the container , Generally, the algorithm operates on the container through the iterator ; Iterators are like pointers , A pointer is a generalization , Can point to elements in the container ; Allocators are used to allocate memory space to elements in containers , The adapter is like a transformer , Fit the components of the .（ Personal understanding , If there is any mistake, please point out ）

Code example ：

About the classification of containers ：

Containers fall into three broad categories ：

1.sequence

        array： Fixed length

        vector： Before closed after opening 、end Point to the position after the last element 、 The elements are not necessarily stored in a continuous space 、vector Each expansion of memory is twice as large （eg: Allocate space for the first time 1, The second space is expanded to 2, The third expansion is 4....)

        deque: Both ends can be inserted or deleted （stack、queue There are two Limited deque）

        list: Double ended chain storage , Space dynamic expansion

        forward-list： Single chain storage

2.associative

        set/multiset： Have their own find function , Red black tree storage method ,set Storing the same content element is not supported ,multiset Support storing the same content elements .

        map/multimap： With <key,value> Of pair Store data in form , Have their own find function , Red black tree storage method ,multimap The use of... Is not supported in [i] Insertion of form , stay map The same... Is not allowed in key The value is .

3.unordered

        unordered set/multiset   unordered map/multimap The storage form is as follows , With hash table Form storage of .

Add ：deque Memory allocation form