Solidity Basic Solidity (Web Dev) 3

Question 1

Which Solidity construct is used to emit a log that can be listened to off-chain?

Accepted Answer

emit EventName()

Answer

The 'emit' keyword is used to trigger an event, which is stored in transaction logs.

Question 2

What is the purpose of the 'constructor' function in a Solidity contract?

Accepted Answer

It runs once when the contract is deployed

Answer

The constructor runs exactly once at deployment and is used to initialize contract state.

Question 3

Which keyword allows a Solidity contract to inherit from another contract?

Accepted Answer

is

Answer

Solidity uses the 'is' keyword for inheritance, e.g., 'contract Child is Parent'.

Question 4

What does the 'storage' keyword indicate when used as a data location in Solidity?

Accepted Answer

The variable persists on the blockchain between calls

Answer

Storage variables are persistent and saved to the blockchain, making reads/writes more expensive.

Question 5

How do you send Ether from a contract to an address in modern Solidity (0.8+)?

Accepted Answer

payable(address).transfer(amount)

Answer

In Solidity 0.8+, you must cast to payable before calling .transfer(), e.g., payable(addr).transfer(amount).

Solidity Practice Test