std::map

`std::map` is a data structure in C++ that stores key-value pairs, where each key is unique. Think of it like a digital dictionary: you look up a word (key) to find its definition (value). It automatically sorts entries based on the keys, allowing efficient searching, insertion, and deletion. This makes `std::map` useful for managing data that needs quick access via unique identifiers, such as mapping user IDs to user information or product codes to details. It maintains an ordered collection, ensuring consistent traversal from smallest to largest keys.