# <map>

**[<map>](https://en.cppreference.com/w/cpp/header/map)** is an ordered associative container: a sorted tree of key-value pairs with O(log n) insertion, deletion, and lookup. It maintains keys in sorted order and allows iteration from min to max.

Use `std::unordered_map` if you don't need order; use `std::map` if you do or if you need to iterate a range of keys.

## Example

This example builds a map of names to ages, iterates through in sorted order, and looks up a specific key.

```cpp
// compile: g++ -std=c++11 -o mapexample mapexample.cpp
// run: ./mapexample
// description: map insertion and lookup

#include <map>
#include <iostream>
#include <string>

int main() {
    std::map<std::string, int> age;
    age["alice"] = 30;
    age["bob"] = 25;
    age["charlie"] = 35;
    
    for (const auto& [name, years] : age) {
        std::cout << name << ": " << years << "\n";
    }
    
    std::cout << "alice is " << age["alice"] << "\n";
    
    return 0;
}
```