STL-vector

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
    int i;
    vector<int> vi(2,9);
    cout << "size=" << vi.size() << endl; //size=2
    cout << "capacity" << vi.capacity() << endl; //capacity=2

    vi.push_back(1);
    cout << "size=" << vi.size() << endl; //size=3
    cout << "capacity" << vi.capacity() << endl; //capacity=4（倍增）

    vi.push_back(2);
    cout << "size=" << vi.size() << endl; //size=4
    cout << "capacity" << vi.capacity() << endl; //capacity=4

    vi.push_back(3);
    cout << "size=" << vi.size() << endl; //size=5
    cout << "capacity" << vi.capacity() << endl; //capacity=8（倍增）

    vi.push_back(4);
    cout << "size=" << vi.size() << endl; //size=6
    cout << "capacity" << vi.capacity() << endl; //capacity=8

    for(i = 0; i < vi.size(); ++i)
        cout << vi[i] << ' '; //9 9 1 2 3 4
    cout << endl;

    vi.push_back(5);
    cout << "size=" << vi.size() << endl; //size=7
    cout << "capacity" << vi.capacity() << endl; //capacity=8

    for(i = 0; i < vi.size(); ++i)
        cout << vi[i] << ' '; //9 9 1 2 3 4 5
    cout << endl;

    vi.pop_back(); //弹出5
    vi.pop_back(); //弹出4
    cout << "size=" << vi.size() << endl; //size=5
    cout << "capacity" << vi.capacity() << endl; //capacity=8

    vi.pop_back(); //弹出3
    cout << "size=" << vi.size() << endl; //size=4
    cout << "capacity" << vi.capacity() << endl; //capacity=8

    vector<int>::iterator itervi = find(vi.begin(), vi.end(), 1);//迭代器指向元素1
    if(itervi != vi.end())
        vi.erase(itervi); //删除元素1

    cout << "size=" << vi.size() << endl; //size=3
    cout << "capacity" << vi.capacity() << endl; //capacity=8
    for(i = 0; i < vi.size(); ++i)
        cout << vi[i] << ' '; //9 9 2 
    cout << endl;

    itervi = find(vi.begin(), vi.end(), 2); //迭代器指向元素2
    if(itervi != vi.end())
        vi.insert(itervi, 3, 7); //在迭代器指向位置的前面插入3个7

    cout << "size=" << vi.size() << endl; //size=6
    cout << "capacity" << vi.capacity() << endl; //capacity=8
    for(i = 0; i < vi.size(); ++i)
        cout << vi[i] << ' '; //9 9 7 7 7 2 
    cout << endl;

    vi.clear(); //清楚所有元素
    cout << "size=" << vi.size() << endl; //size=0
    cout << "capacity" << vi.capacity() << endl; //capacity=8

    system("pause");
    return 0;
}