How can I traverse/iterate an STL map?

Question

I want to traverse an STL map. I don\'t want to use its key. I don\'t care about the ordering, I just look for a way to access all elements it contains. How can I do this?

Answer 1

C++17

Since C++17 you can use range-based for loops together with structured bindings for iterating over a map. The resulting code, e.g. for printing all elements of a map, is short and well readable:

std::map m{ {3, "a"}, {5, "b"}, {9, "c"} };

for (const auto &[k, v] : m)
    std::cout << "m[" << k << "] = " << v << std::endl;

Output:

m[3] = a
m[5] = b
m[9] = c

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