Constructor function in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a constructor function in a smart contract?

A constructor function is a special function that runs only once when the smart contract is created. It sets up initial values or settings for the contract.

beginner

When is the constructor function executed?

The constructor function is executed automatically during the deployment of the smart contract, before any other functions can be called.

beginner

Can a smart contract have more than one constructor function?

No, a smart contract can only have one constructor function. It is unique and used to initialize the contract once.

intermediate

How do you define a constructor function in Solidity (Ethereum's language)?

In Solidity, you define a constructor using the keyword 'constructor()' followed by its code block. For example: constructor() { /* initialization code */ }

beginner

Why is the constructor function important in blockchain smart contracts?

It sets the initial state of the contract, like owner address or initial balances, ensuring the contract starts correctly and securely.

When does the constructor function run in a smart contract?

A Only once during contract deployment

B Every time a function is called

C When the contract is destroyed

D When a user sends a transaction

The constructor runs only once when the contract is deployed to set initial values.

How many constructor functions can a smart contract have?

A Two

B One

C As many as needed

D None

A smart contract can have only one constructor function.

Which keyword is used to define a constructor in Solidity?

A init

B setup

C constructor

D start

The keyword 'constructor' defines the constructor function in Solidity.

What is a common use of a constructor function?

A Initialize contract state variables

B Destroy the contract

C Send tokens

D Call other contracts

Constructors usually initialize important variables like owner or balances.

Can the constructor function be called after deployment?

A Only by the owner

B Yes, anytime

C Only if the contract is paused

D No, it runs only once during deployment

The constructor cannot be called again after deployment.

Explain what a constructor function is and why it is used in blockchain smart contracts.

Think about what happens when you first create a contract.

Describe how to write a constructor function in Solidity and what it typically contains.

Look for the special function named 'constructor' in Solidity.