如何通过引用推送向量？(How do I push vectors by reference?)

 下面的代码不起作用，因为我将矢量a和b推回到矢量矢量，然后改变矢量a和b。 我想改变矢量a和b，以便矢量矢量遭受相同的修改。 我该怎么做呢？ 
 
#include <iostream>
#include <vector>

int main()
{
std::vector<std::vector<int>>vector;
std::vector<int>a;
std::vector<int>b;
vector.push_back(a);
vector.push_back(b);
for (int i = 1; i <= 10; i++)
    a.push_back(i);
for (int i = 11; i <= 20; i++)
    b.push_back(i);
std::cout << vector[1][0];
std::cin.get();
}

This code below doesn't work because I push_back the vectors a and b to the vector vector and then alter the vectors a and b. I want to alter the vectors a and b so that the vector vector suffers the same modifications. How do I do this?
 
#include <iostream>
#include <vector>

int main()
{
std::vector<std::vector<int>>vector;
std::vector<int>a;
std::vector<int>b;
vector.push_back(a);
vector.push_back(b);
for (int i = 1; i <= 10; i++)
    a.push_back(i);
for (int i = 11; i <= 20; i++)
    b.push_back(i);
std::cout << vector[1][0];
std::cin.get();
}

原文：https://stackoverflow.com/questions/50614970