Simple application of C++--vector

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

1 Basic operations

(1) header file #include<vector>.

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

(3) Insert number at tail: vec.push_back (a);

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

(5) Use iterators to access elements.

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 first 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. Here are some of the uses of my own tests, for reference only:

#include <iostream>#include<vector>#include<stdio.h>using namespaceStd;typedefstructa{intID; intlength; intwidth; //for some of the elements of the vector is a struct, you can define the comparison function in the structure, the following sort in ascending order of Id,length,width    BOOL operator< (ConstA &a)Const{        if(id!=a.id)returnid<a.id; Else{            if(length!=a.length)returnlength<a.length; Else                returnwidth<A.width; }}}a;intmain () {vector<int>VI; Vi.push_back ( A);//This is the element that is inserted from the end of the vectorVi.push_back ( -); Vi.pop_back ();//remove an element from the endVi.push_back ( +); Vector<int>::iterator ITER;//Iterating through an element in a vector through an iterator      for(Iter=vi.begin (); Iter!=vi.end (); iter++) {cout<<*iter<<" "; } cout<<Endl; Vi.insert (Vi.begin ()+1,2);//inserts an element at the specified location       for(Iter=vi.begin (); Iter!=vi.end (); iter++) {cout<<*iter<<" "; } cout<<Endl; Vi.erase (Vi.begin ()+1);//deletes the element at the specified position        for(Iter=vi.begin (); Iter!=vi.end (); iter++) {cout<<*iter<<" "; } cout<<Endl; Vi.erase (Vi.begin ()+1, Vi.end ());//This is the deletion of the specified interval of the element, the interval is "I,j"        for(Iter=vi.begin (); Iter!=vi.end (); iter++) {cout<<*iter<<" "; } cout<<Endl; //Testing of vectorsVector <A>VEC; A;//initialize a struct elementA.id=1; A.length=2; A.width=3; Vec.push_back (a);//INSERT INTO VectorVector<a>:: iterator ite; Ite=Vec.begin (); cout<< (*ite) .id<<" "<< (*ite) .length<<" "<< (*ite) .width<<Endl;}

3. Here are some simple algorithms, there are other algorithms if necessary, please refer to the STL source analysis

(1) Flip the element with reverse: Requires a header file #include<algorithm>

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) Sorting by using sort: Requires header file #include<algorithm>

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;
}

Simple application of C++--vector