Iterate through HashMap C++

Question

How can I iterate through a hashMap (C++) so I can go through all the elements?

I have this hash named map:

HashMap<std::string, int> map;

map.insert (key1, value1);
map.insert (key2, value2);
map.insert (key3, value3);

    ...
    ...
    ...

map.insert (keyN, valueN);

What have you tried? It shouldn't be any different than any other container. — NathanOliver, May 04 '17 at 15:51
Possible duplicate of [How to loop through a C++ map of maps?](http://stackoverflow.com/questions/4844886/how-to-loop-through-a-c-map-of-maps) — Borgleader, May 04 '17 at 15:51
`HashMap` is not a part of C++. If you are using a third party library, you need to study its documentation. — n. m. could be an AI, May 04 '17 at 16:05

ΦXocę 웃 Пepeúpa ツ · Answer 1 · 2017-05-04T16:00:21.713

hash_map is deprecated, but the same principle applies... you can use a range loop (in this case with an unordered_map)

using auto will make it like:

#include <iostream>
#include <string> 
#include <unordered_map>
int main()
{
    std::unordered_map<std::string, int> myMap;

    myMap.insert(std::pair<std::string, int>("a", 1));
    myMap.insert(std::pair<std::string, int>("b", 2));
    myMap.insert(std::pair<std::string, int>("c", 3));
    myMap.insert(std::pair<std::string, int>("d", 4));
    for (const auto& x : myMap)
    {
        std::cout << "fisrt: " << x.first << ", second: " << x.second << std::endl;
    }
    std::cin.get();
    return 0;
}

score 0 · Answer 2 · answered May 04 '17 at 15:54

0

If it has both a begin() and end() member functions you should be able to simply put it in a range loop.

for (auto& entry : map)
    //whatever you want here

answered May 04 '17 at 15:54

Jack Fenech

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Iterate through HashMap C++

2 Answers2