Introduction to Basic Functions in Solidity Programming

Functions in Solidity enable specific code execution, allowing users to update and retrieve stored values efficiently.

### Understanding Basic Solidity Functions: Creating and Using the `store` Function
* 🛠 In Solidity, functions are defined using the `function` keyword, and they allow us to **execute specific tasks** within our smart contract code.
* 🔢 We can create a function named `store` that updates our favorite number by accepting a parameter called **_favoriteNumber**, which is of type **uint256**.
* 🔒 This function is marked as **`public`**, meaning it can be accessed both internally and externally, and it sets the **`favoriteNumber`** variable to the value of **`_favoriteNumber`**.
* 🚀 After compiling the code, we can deploy the contract in a simulated environment using Remix IDE, where we can **interact with our contract without dealing with real blockchain complexities**.
* 📊 Upon deployment, we can see our **contract address** and a button to call the `store` function, which allows us to **update the favorite number** stored on the blockchain.
* 🔍 To make the `favoriteNumber` visible externally, we can add the `public` keyword, enabling us to **retrieve its value using a getter function** automatically generated by Solidity.
* ⚙ Functions in Solidity have different visibility specifiers: `public`, `private`, `external`, and `internal`, with **`public` allowing access from other contracts and users**.
* 💰 Calling functions that modify the blockchain state, like `store`, incurs **gas costs**, while `view` functions that only read state, like a custom `retrieve` function, do not require gas unless called within a **state-modifying transaction**.

Lesson 2 Part 4 | Solidity Functions - Solidity & Foundry Full Course

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Functions are subsections of code executing specific tasks when called.

Functions are defined using the `function` keyword, followed by the function name and parentheses for parameters.

Parameters are defined with their type and name (different from state variables).

Example: `store` function updates `favoriteNumber` with a passed `uint256` value.

Deploying and Running Smart Contracts in Remix

Compilation and deployment to a simulated Remix VM environment.

Deployment to a fake environment avoids complexities of testnets/mainnets.

Remix VM provides fake accounts and gas for transactions.

Deployed contract's address is displayed, similar to wallet addresses.

Terminal shows transaction details (status, hash, etc.).

Default visibility is `internal`; `public` makes variables/functions externally accessible.

Visibility specifiers: `public`, `private`, `external`, `internal`.

`public` creates getter functions for state variables.

`internal` restricts access to the current contract.

`external` is for functions only, accessible externally but not internally.

Updating state (e.g., calling `store`) costs more gas than simple ETH transfers.

Adding operations within a function increases gas costs.

Variables are accessible only within their defined scope (curly brackets).

Compilation errors occur when accessing variables outside their scope.

`view` functions read state without modifying it, and don't require transactions.

`view` and `pure` keywords prevent state modification.

`pure` functions neither read nor write from state.

View/pure functions are blue buttons; calls don't send transactions.

Gas cost applies to view/pure functions only when called by a transaction-requiring function.