map in C++

In C++, the dictionary data structure is called a map.
```
#include <map>
#include <iostream>
using namespace std;

int main() {
    map<int, int> m;
    m[1] = 1;
    m[2] = 2;
    if(m.find(1)!=m.end()) {
        cout << m[1] << endl;
    }
    for(auto it = m.begin(); it != m.end(); it++) 
        cout << it->first << "=>" << it->second << "; ";
}
```