c++ vector 迭代器 demo

1.

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

int main()
{
    vector<int> v(5);
    cout<<"sizeof(v)="<<sizeof(v)<<endl;
    v[0] =200;  
    v[1] =200;  
    v[2] =200;  
    v[3] =200;  
    v[4] =200;  
    cout<<"1 v.size()="<<v.size()<<endl;
    v.push_back(500);
    cout<<"2 v.size()="<<v.size()<<endl;
    int i;
    for(i=0;i<6;i++)
        cout<<v[i]<<" ";
    cout<<endl;
    return 0;
}

2

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

int main()
{
    vector<int> v(5);
    cout<<"sizeof(v)="<<sizeof(v)<<endl;
    v[0] =200;  
    v[1] =200;  
    v[2] =200;  
    v[3] =200;  
    v[4] =200;  
    cout<<"1 v.size()="<<v.size()<<endl;
    v.push_back(500);
    cout<<"2 v.size()="<<v.size()<<endl;
#if 0
    int i;
    for(i=0;i<6;i++)
        cout<<v[i]<<" ";
    cout<<endl;
#else
    for(auto k:v)
        cout<<k<< " ";
    cout<<endl;
#endif
    //迭代器
    vector<int>::iterator it;
    for(it = v.begin();it != v.end();++it)
        cout<<*it<<" ";
    cout<<endl;

    return 0;
}