STL--vector

STL--vector

菜菜的学习了一下STL的vector，做一下笔记感觉这个网站讲得通俗易懂http://www.cppreference.com/cppvector/index.html 写了一下测试code(待续)

C++ Vectors

Vectors contain contiguous elements stored as an array. Accessing members of a vector or appending elements can be done in constant time, whereas locating a specific value or inserting elements into the vector takes linear time.

Display all entries for C++ Vectors on one page, or view entries individually:

Vector constructors	create vectors and initialize them with some data
Vector operators	compare, assign, and access elements of a vector
assign	assign elements to a vector
at	returns an element at a specific location
back	returns a reference to last element of a vector
begin	returns an iterator to the beginning of the vector
capacity	returns the number of elements that the vector can hold
clear	removes all elements from the vector
empty	true if the vector has no elements
end	returns an iterator just past the last element of a vector
erase	removes elements from a vector
front	returns a reference to the first element of a vector
insert	inserts elements into the vector
max_size	returns the maximum number of elements that the vector can hold
pop_back	removes the last element of a vector
push_back	add an element to the end of the vector
rbegin	returns a reverse_iterator to the end of the vector
rend	returns a reverse_iterator to the beginning of the vector
reserve	sets the minimum capacity of the vector
resize	change the size of the vector
size	returns the number of items in the vector
swap	swap the contents of this vector with another

 1 #include < vector >
 2 #include < iostream >
 3 #include < algorithm >
 4 using   namespace  std;
 5 void  print( int  a) {cout<<a<<" ";}
 6 int  main()
 7 {
 8    vector<int>v,v1;
 9    vector<int>::iterator iv1,iv2;
10    vector<int>v2;
11    v2.reserve(10);    
12    v.assign(10,2);
13    cout<<v2.capacity()<<endl;//capacity容量输出为10
14    cout<<v2.size()<<endl;//大小输出为1
15    int i;
16    for(i=0;i<7;i++)v2.push_back(i);
17    for_each(v2.begin(),v2.end(),print);
18    cout<<endl;
19    for(iv1=v2.begin();iv1!=v2.end();iv1++)
20        if(*iv1==3)break;
21    if(iv1!=v2.end())v2.insert(iv1,99);
22    for_each(v2.begin(),v2.end(),print);
23    cout<<endl;
24    if(iv1!=v2.end())v2.insert(iv1,5,99);
25    for_each(v2.begin(),v2.end(),print);
26    cout<<endl;
27    if(iv1!=v2.end())v2.insert(iv1,v.begin(),v.end());
28    for_each(v2.begin(),v2.end(),print);
29    cout<<endl;
30    cout<<v2.size()<<endl;
31    v2.erase(v2.begin());
32    cout<<v2.size()<<endl;
33    v2.erase(v2.begin(),v2.end());
34    for_each(v2.begin(),v2.end(),print);
35    iv1=v.begin();iv2=v.end();
36    cout<<v.begin()<<endl;
37    cout<<v.end()<<endl;
38    cout<<iv1<<endl;
39    cout<<iv2<<endl;
40//    for(i=0;i<15;i++)cout<<v[i]<<" ";
41//    cout<<endl;
42//    for(i=0;i<15;i++)cout<<v.at(i)<<" ";//at()函数更加安全；
43//    cout<<endl;
44    for_each(v.begin(),v.end(),print);
45    cout<<endl;
46//    v1.assign(v.begin(),v.end());
47//    v1.assign(iv1+2,iv2-2);
48//    for(i=0;i<10;i++)cout<<v1[i]<<' ';
49//    cout<<endl;
50    for(i=0;i<10;i++)v1.push_back(i);
51    for_each(v1.begin()+1,v1.end()-2,print);//输出begin开始指向的数据，直到end指向的前一个数据
52    for_each(v1.begin(),v1.end(),print);
53    cout<<endl;
54    cout<<v1.back()<<endl;
55    cout<<v1.front()<<endl;
56    cout<<v1.size()<<endl;
57    v.clear();
58    cout<<v.size()<<endl;
59    for_each(v.begin(),v.end(),print);//已经clear，begin==end，不会有任何结果。
60    return 0;
61}
62
63
64
65 // 试了一下结构体,感觉自己简直太水了，努力学习中！
66
67 #include < iostream >
68 #include < vector >
69 using   namespace  std;
70 typedef  struct  node {
71    int x;
72    int y;
73} node;
74 ostream  operator << (ostream  in ,node a) {
75    in<<a.x<<a.y<<endl;
76    return in;
77}
78 int  main()
79 {
80    vector<node>v(10);
81    v[0].x=1;v[0].y=1;
82    vector<node>::iterator iv(v.begin());
83    cout<<v[0].x<<v[0].y<<endl;
84    cout<<*iv<<endl;
85    cout<<iv->x<<iv->y<<endl;
86    return 0;
87}