Vector 的简单用法

/*
* @Author: Achan
* @Date:   2019-04-06 22:39:50
* @Last Modified by:   Achan
* @Last Modified time: 2019-04-06 23:22:19
*/
#include<bits/stdc++.h>
using namespace std; 
inline bool cmp(int a, int b){ 
	return a > b; 
}
int main(void)
{
    int n = 3;
    int m = 4;

    //Init
    vector <vector<int> > a(n,vector<int>(m)); // a[n][m]  n行m列二维数组 
    //vector<vector<int>> vec(n,vector<int>(m,1)) //初始化为1 也可以为其他数


    for(int i=0; i<n; ++i)
        for(int j=0; j<m; ++j)
            a[i][j] = i+j;
    for(int i=0; i<n; ++i)
        for(int j=0; j<m; ++j)
            cout << a[i][j] <<(j != m-1?" ":"\n");



   //Copy
   //std::vector<int> b(a[0].begin(),a[0].end());//数组copy   
   std::vector<int> b(a[0].begin(),a[0].begin() + m);//数组copy前m个    





   //Sort
   sort(b.begin(),b.begin()+m,cmp);  //降序sort前m个
  // sort(b.begin(),b.end()); //默认升序sort



   //Add
   int tes = 5;
	//b.emplace_back(tes);   
   b.push_back(tes); 




    for(int i=0; i<m+1; ++i)
            cout << b[i] <<(i != m-1?" ":"\n");
    return 0; 
}