#include <iostream>
#include <iomanip>
#include <vector>
 
using Inner = std::vector<int>;
using Outer = std::vector<Inner>;
 
std::ostream& operator <<(std::ostream& os, const Inner& row)
{
    for (auto col : row)
        std::cout << col << ' ';
    return os;
}
 
std::ostream& operator <<(std::ostream& os, const Outer& tbl)
{
    for (auto const& row : tbl)
        std::cout << row << '\n';
    return os;
}
 
int main()
{
    Inner inner;
    for (int i=1; i<=10; ++i)
        inner.emplace_back(i);
 
    Outer outer(10, inner);
 
    // iterators
    for (auto row = outer.begin(); row != outer.end(); ++row)
    {
        for (auto col = row->begin(); col != row->end(); ++col)
            std::cout << *col << ' ';
        std::cout.put('\n');
    }
    std::cout.put('\n');
 
    // ranged-for
    for (auto const& row : outer)
    {
        for (auto col : row)
            std::cout << col << ' ';
        std::cout.put('\n');
    }
    std::cout.put('\n');
 
    // stream overloads
    std::cout << outer << '\n';
}
 

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