C++ vector demo

#include <iostream>
#include <vector>
#include <array>
using namespace std;
void PrintVector(vector<int> v_int) {
    cout << "PrintVector:";
    for (int i = 0; i < v_int.size(); i++)
    {
        cout << v_int[i] << " ";
    }
    cout << endl;
    return;
}
void PrintVector2(vector<int> v_int) {
    cout << "PrintVector2:";
    vector<int>::iterator it;
    for (vector<int>::iterator it = v_int.begin(); it != v_int.end(); it++)
    {
        cout << *it << " ";
    }
    cout << endl;
    return;
}
int main() {
    vector<int> v_int;
    cout << "push 1" << endl;
    if (v_int.size() < v_int.max_size())
    {
        v_int.push_back(1);
    }
    v_int.push_back(2);
    v_int.push_back(1);
    cout <<"R v_int[0]:" <<v_int[0] << "  size:"<<v_int.size()<<endl;
    cout << "R v_int.at(0):" << v_int.at(0) << "  size:" << v_int.size() << endl;
    //cout << "R v_int.at(1):" << v_int.at(1) << endl;  //越界
    //cout << "R v_int[1]:" << v_int[1] << endl;  //越界
    PrintVector(v_int);
    PrintVector2(v_int);
    v_int.pop_back(); //erase ele at end
    PrintVector2(v_int);
    v_int.push_back(3);
    v_int.push_back(1);
    v_int.push_back(2);
    PrintVector2(v_int);
    v_int.erase(begin(v_int)+3);
    PrintVector2(v_int);
    
    getchar();
}

 

显示：

push 1
R v_int[0]:1 size:3
R v_int.at(0):1 size:3
PrintVector:1 2 1
PrintVector2:1 2 1
PrintVector2:1 2
PrintVector2:1 2 3 1 2
PrintVector2:1 2 3 2