Vector container in C + +

In C + +, vector is a very useful container, and here is a summary of the container.

1. Basic operation

(1) header file #include <vector>.

(2) Create vector object vector<int> VEC;

(3) Insertion of the trailing digit vec.push_back (a);

(4) Use subscript to access element cout<<vec[0]<<endl; //Remember that the subscript is starting from 0.

(5) using iterators to access elements

Vector<int>::iterator it;for (It=vec.begin (); It!=vec.end (); it++)
{
cout<<*it<<endl;
}

(6) inserting element Vec.insert (Vec.begin () +i,a); //Insert a in front of the first I+1 element

(7) Delete element Vec.erase (Vec.begin () +2); //Delete element 3rd

Vec.erase (Vec.begin () +i,vec.end () +j); //delete interval [i,j-1]; interval starting from 0

(8) Vector size vec.size ();

(9) empty vec.clear ();

Note: Vector elements can not only make the int,double,string, but also the structure, but note: The structure should be defined as global, otherwise it will be wrong.

2. Algorithm

Header file Required #include<algorithm>

(1) Using reverse to flip elements

Reverse (Vec.begin (), Vec.end ()); Flips the element (in a vector, if two iterators are required in a function,

Usually the latter is not included.)

(2) Sort by using sort

Sort (Vec.begin (), Vec.end ());(by default in ascending order, that is, from small to large).

You can compare functions in descending order by overriding the sort comparison, as follows:

To define a sort comparison function:

BOOL Comp (const int &A,CONST int &b)
{
Return a>b;
}
Called When: Sort (Vec.begin (), Vec.end (),Comp), so that it is sorted in descending order.

Vector container in C + +