Ch8-10 | Notion

The delete operator can reset the value of the variable to their default value.

What is the difference between the constant and immutable keywords in Solidity and how do I use them?

Feature	`constant`	`immutable`
Assignment Time	Compile-Time	At Declaration(Compile-Time) or Constructor(Deployment-Time)
Flexibility	Less flexible; values must be known upfront	More flexible; values can be set during deployment
Use Cases	Fixed values like mathematical constants, fixed addresses	Dynamic values like deployer address, configuration parameters
Gas Efficiency	Slightly more efficient due to compile-time embedding	Efficient; stored in bytecode after deployment
Reassignment	Not allowed after initial assignment	Not allowed after initial assignment

<aside> 💡

immutable Variables:

Assignment: Either at declaration (if value is known at compile-time) or within the constructor (if value is determined at deploy-time).
Use Cases: Deploy-time settings like owner addresses, deployment timestamps, constructor-based configurations.

Assignment in Constructor:

Purpose: Set values that are dynamic or dependent on external factors during deployment.
How: Assign the immutable variable within the constructor body, using constructor parameters or deploy-time data (e.g., msg.sender, block.timestamp). </aside>

Aspect	Compile Time	Deploy Time
When It Occurs	Before deploying the contract	During the actual deployment to the blockchain
What’s Set	Values known beforehand (constants)	Values determined at deployment (immutable variables)
Examples	`constant` variables like `MAX_SUPPLY`	`immutable` variables like `owner` set in the constructor
Analogy	Writing and baking the recipe	Opening the bakery to the public

Use constant for values that never change and are known upfront: Like the maximum number of tokens (MAX_SUPPLY).
Use immutable for values that are set once when the contract is deployed: Like the owner’s address, which you might not know until deployment.