hashmap in cpp

1#include <unordered_map>
2#include <iostream>
3
4int main()
5{
6    std::unordered_map<std::string, int> age;
7    // Insert
8    age["Michael"] = 16;
9    age.insert(std::pair<std::string, int>{"Bill", 25});
10    age.insert({"Chris", 30});
11
12    // Search and change
13    age["Michael"] = 18;
14    age.at("Chris") = 27;
15
16    // Check if key exists
17    std::string query;
18    query = "Eric";
19    if (age.find(query) == age.end())
20    {
21        std::cout << query << " is not in the dictionary!" << std::endl;
22    }
23
24    // Delete
25    query = "Michael";
26    if (age.find(query) == age.end())
27    {
28        std::cout << query << " is not in the dictionary!" << std::endl;
29    }
30    age.erase(query);
31    if (age.find(query) == age.end())
32    {
33        std::cout << query << " is not in the dictionary!" << std::endl;
34    }
35
36    // Iterate
37    for (const std::pair<std::string, int>& tup : age)
38    {
39        std::cout << "Name: " << tup.first << std::endl;
40        std::cout << "Age: " << tup.second << std::endl;
41    }
42}
43

1#include<unordered_map> //is the stl for unordered map