（ACM模板）不定长数组vector

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

vector<int> a;
vector<int> b[];

int main()
{
    a.push_back();
    a.push_back();
    cout<<a[]<<" "<<a[]<<endl;
    cout<<a.front()<<" "<<a.back()<<endl;

    a.push_back();
    sort(a.begin(),a.end());

    for (int i=;i<a.size();i++)
      cout<<a[i]<<" ";
    cout<<endl;  

    a.pop_back();
    cout<<a[];

    a.empty();  //vector是否为空
    a.clear();  //清空vector       

    return ;
}

发现一个大佬写的Vector一些更骚的用法：https://www.cnblogs.com/zwfymqz/p/7788554.html