Functions and Visibility 👁️

Functions are how your contract interacts with the world. They define what your contract can do, from returning a score to updating a record.

Solidity uses Visibility Levels to decide who can call a function:

• public: Anyone can call it.

• external: Only callable from outside the contract.

• internal: Only this contract or its children can call it.

• private: Only this specific contract has access.

Nice! Remember: Writing to storage is the most expensive thing you can do on-chain. Smart developers optimize their logic to keep gas costs low.

If a function only reads data, mark it as view. If it doesn't even read from storage (maybe it just does math), mark it as pure.