How can I display the content of a map on the console?

Question

I have a map declared as follows:

map < string , list < string > > mapex ; list< string > li;

How can I disp

Answer 1

If you can use C++11 features, then I think range-based for loops as proposed in The Paramagnetic Croissant's answer provide the most readable option. However, if C++17 is available to you, then you can combine those loops with structured bindings to further increase readability, because you no longer need to use the first and second members. For your specific use case, my solution would look as follows:

std::map> mapex;
mapex["a"] = { "1", "2", "3", "4" };
mapex["b"] = { "5", "6", "7" };

for (const auto &[k, v] : mapex) {
    std::cout << "m[" << k.c_str() << "] =";
    for (const auto &s : v)
        std::cout << " " << s.c_str();
    std::cout << std::endl;
}

Output:

m[a] = 1 2 3 4
m[b] = 5 6 7

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