[c++] vector的使用

 1 #include<iostream>
 2 #include<vector>
 3 using namespace std;
 4 
 5 void print( vector<int> &vec )
 6 {
 7     for ( vector<int>::iterator it = vec.begin(); it!=vec.end(); it++ )
 8         cout<<*it<<' ';
 9     cout<<endl;
10 }
11 
12 void push( vector<int> &vec, int value )
13 {
14     vec.push_back(value);
15 }
16 
17 int main()
18 {
19     vector<int> first;
20     vector<int> second (4,100); // four ints with value 100
21     print(second);
22     vector<int> third ( second.begin()+1, second.end() );
23     print(third);
24     vector<int> fourth (third);
25 
26     //construct from arrays
27     int arrays[] = {1,2,3,4,5,6};
28     vector<int> fifth ( arrays, arrays + sizeof(arrays)/sizeof(int) );
29 
30     print(fifth);
31     push(fifth, 20);
32     print(fifth);
33     fifth.pop_back();
34     print(fifth);
35     fifth.pop_back();
36     print(fifth);
37 
38     cout<<"capacity is "<<fifth.capacity()<<endl;
39     cout<<"size is "<<fifth.size()<<endl;
40     fifth.reserve(20);
41     cout<<"capacity is "<<fifth.capacity()<<endl;
42     cout<<"size is "<<fifth.size()<<endl;
43     print(fifth);
44 
45     // erase the first 3 elements:
46     fifth.erase(fifth.begin(), fifth.begin()+3);
47     for (int i=0; i<fifth.size(); i++ )
48         cout<<fifth[i]<<' ';
49     cout<<endl;
50 
51     return 0;
52 }