容器可以理解为数组，容器嵌套一个容器，即数组内嵌套一个数组，则为二维数组，遍历则为for循环的嵌套

#include<iostream>
using namespace std;
#include<vector>//容器嵌套容器
void test()
{vector<vector<int>> v;//创建小容器vector<int> v1;vector<int> v2;vector<int> v3;vector<int> v4;//向小容器中添加数据	for (int i = 0; i < 4; i++){v1.push_back(i + 1);v2.push_back(i + 2);v3.push_back(i + 3);v4.push_back(i + 4);}//将小容器插入到大容器中v.push_back(v1);v.push_back(v2);v.push_back(v3);v.push_back(v4);//通过大容器把所有数据遍历一遍for (vector<vector<int>>::iterator it = v.begin(); it != v.end(); it++){//(*it) --- 容器 vector<int>for (vector<int>::iterator vit = (*it).begin(); vit != (*it).end(); vit++){cout << *vit << " ";}cout << endl;}
}int main()
{test();return 0;
}