C + + linear sequence container <vector> Simple summary

C + + linear sequence container <vector> Simple summary

The vector is a variable-length array, which is used without the need to declare the upper bound, and as the element increases, the length of the vector increases automatically; the vector class provides an extra way to add and remove elements, which is more efficient than array operations.

Header files: #include <vector>

Namespaces: Using Namespace Std:vector

constructor function

vector<int>vec_int; Create a vector of a shaping element

vector<string>vec_string; Creates a vector of a string element

vector<mystruct>vec_mystruct; Create an element that is a vector of structures

Basic maintenance Operations 1. Access

Subscript access and at () two ways, the second method is recommended, it will be the boundary check.

Vec_int[1], vec_int.at (1);//access the element with index 1, element 2nd

int size () const; Returns the number of elements in a vector

BOOL empty () const; Determines whether the vector is empty, true is empty, false is not empty

Reference back (); Returns a reference to the last element of the vector, which can be modified

Reference Front (); Returns a reference to the first element of the vector, which can be modified

2. Add

void push_back (const t& Val);; adds an element at the end of the vector.

3. Delete

void Pop_back (); deletes the element at the end of the vector .

void Clear (); Clears all elements in the vector

4. Insert

void Insert (iterator it, int count, t& value); Inserts the value of the specified count number at the position of the iterator, with the count parameter optional, which defaults to 1

5. Traverse

It is also very convenient to use the iterator to traverse it frequently.

Iterator begin (); An iterator that returns the first element of a vector

Iterator End (); returns an iterator to the last element of a vector

Traversal method:

 for (vector<int>::iterator vec_it = Vec_int.begin (); Vec_it! = Vec_int.end (); vec_it++)    {< < *vec_it << Endl;}

member functions

Assign	Clears the vector and copies the specified elements to the empty vector.
At	Returns a reference to the element at the specified position in the vector.
Back	Returns a reference to the last element in the vector.
Begin	Returns a random-access iterator to the first element in the vector.
Capacity	Returns the number of elements that a vector can contain without allocating more storage.
Cbegin	Returns a random-access const iterator that points to the first element in a vector.
Cend	Returns a random-access constant iterator that points to the position just above the end of the vector.
Crbegin	Returns a const iterator that points to the first element in a reverse vector.
Crend	Returns a const iterator that points to the end of the inverse vector.
Clear	Clears the elements of the vector.
Data	Returns a pointer to the first element in the vector.
Emplace	Inserts elements of the ground construct into the vector at the specified position.
Emplace_back	Adds an in-place constructed element to the end of the vector.
Empty	Tests whether the vector container is empty.
End	Returns a random-access iterator that points to the end of the vector.
Erase	Removes an element or a series of elements from a vector from a specified location.
Front	Returns a reference to the first element in the vector.
Get_allocator	Returns the object to the allocator class used by the vector .
Insert	Inserts an element or multiple elements into the vector at the specified position.
Max_size	Returns the maximum length of a vector.
Pop_back	Removes the element at the end of the vector.
Push_back	Adds an element at the end of the vector.
Rbegin	Returns an iterator that points to the first element in a reverse vector.
Rend	Returns an iterator that points to the end of the reverse vector.
Reserve	Retains the minimum storage length of the vector object.
Resize	Specifies the new size for the vector.
Shrink_to_fit	Discard additional capacity.
Size	Returns the number of vector elements
Swap	Swaps the elements of two vectors.

C + + linear sequence container <vector> Simple summary