C + + vector

Original: http://www.cnblogs.com/wang7/archive/2012/04/27/2474138.html thank Jinhe.

1 Basic operations

(1) header file #include<vector>.

(2) Creating a Vector object,vector<int> VEC;

(3) Tail Insert number: Vec.push_back (a);

(4) Use subscript to access elements,cout<<vec[0]<<endl; remember that subscripts start at 0.

(5) Accessing elements using iterators.

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

(6) Insert element: Vec.insert (Vec.begin () +i,a); Insert a in front of the i+1 element;

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

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 ();

2

Vector elements can not only make int,double,string, but also structural body, but note: The structure is defined as global, otherwise there will be errors. The following is a short program code:

#include <stdio.h> #include <algorithm> #include <vector> #include <iostream> using namespace

Std
    typedef struct RECT {int id;
    int length; int width;

For vector elements that are structural, you can define comparison functions within the structure, sorted by Id,length,width ascending order.
BOOL operator< (const RECT &a) const
{
if (id!=a.id)
Return id<a.id;
Else
{
if (length!=a.length)
Return length<a.length;
Else
Return width<a.width;
}
}}rect;
    int main () {vector<rect> VEC;
    Rect Rect;
    rect.id=1;
    rect.length=2;
    rect.width=3;
    Vec.push_back (rect);
    Vector<rect>::iterator It=vec.begin ();    

cout<< (*it) .id<< ' << (*it) .length<< ' << (*it) .width<<endl;

return 0; }

3 algorithm

(1) Use reverse to flip the element: Requires a header file #include<algorithm>

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

Usually the latter one is not included.)

(2) Use sort order: Need header file #include<algorithm>,

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

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

To define a sort comparison function:

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