Ethereum Developer Solidity Smart Contract Development 2

Question 1

What is the Solidity `constructor` function used for?

Accepted Answer

Initializing contract state when it is deployed

Answer

The `constructor` runs once during contract deployment and is used to set initial state variables.

Question 2

What does the `emit` keyword do in Solidity?

Accepted Answer

Fires an event that gets logged on the blockchain

Answer

The `emit` keyword triggers an event, recording a log entry in the transaction receipt on the blockchain.

Question 3

Which Solidity keyword marks a state variable as unchangeable after deployment?

Accepted Answer

immutable

Answer

The `immutable` keyword allows a variable to be set in the constructor but never changed afterward.

Question 4

What is a Solidity `modifier` used for?

Accepted Answer

Reusing pre- and post-condition logic across multiple functions

Answer

Modifiers wrap function execution with reusable guard logic, like access control checks, using `_;` as a placeholder.

Question 5

What is the difference between `memory` and `storage` in Solidity?

Accepted Answer

memory is temporary and wiped after execution; storage persists on-chain

Answer

`memory` variables exist only during function execution while `storage` variables persist permanently on the blockchain.

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