今日课堂练习：vector构造函数

#include <iostream>
#include <vector>
using namespace std;

void printVector(vector<int> &v)
{
    vector<int>::iterator iter;

    for(iter=v.begin(); iter != v.end(); iter++)
    {
    cout << *iter << " ";
    }
    cout << endl;
}

int main()
{
    vector<int> v;
    v.push_back(10);
    v.push_back(20);
    v.push_back(30);
    v.push_back(40);
    v.push_back(50);

    printVector(v);

    vector<int> v2 = v;
    printVector(v2);

    vector<int> v3(v2.begin()+2, v2.end());
    printVector(v3);

    return 0;
}