Return values in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a return value in a blockchain smart contract function?

A return value is the data that a smart contract function sends back after it finishes running. It tells you the result of the function's work.

beginner

Why are return values important in blockchain programming?

Return values let other parts of the program or users know what happened inside the contract, like if a transaction succeeded or what data was found.

intermediate

Can a blockchain smart contract function return multiple values?

Yes, some blockchain languages like Solidity allow functions to return multiple values using tuples or structs.

beginner

What happens if a smart contract function does not have a return statement?

If a function does not return anything, it means it only changes the contract's state or performs actions without sending back data.

intermediate

How do return values affect gas costs in blockchain transactions?

Returning data can increase gas costs because the blockchain stores or sends the returned data, so simpler return values can save gas.

What does a return value from a smart contract function represent?

A The result or output of the function

B The amount of cryptocurrency sent

C The transaction fee paid

D The contract's address

A return value is the output data that a function sends back after execution.

Can a smart contract function return more than one value?

A Yes, using tuples or structs

B Only if the contract is deployed on Ethereum

C No, only one value can be returned

D Only if the function is marked payable

Functions can return multiple values using tuples or structs in languages like Solidity.

What happens if a function has no return statement?

A It returns the contract's balance

B It returns nothing and only performs actions

C It returns zero by default

D It causes an error

Functions without return statements perform actions but do not send back data.

How do return values affect gas costs?

A Gas costs depend only on contract size

B Returning data always reduces gas costs

C Gas costs are not affected by return values

D Returning data can increase gas costs

Returning data can increase gas costs because the blockchain processes and stores the returned data.

Which of these is a reason to use return values in smart contracts?

A To send cryptocurrency to users

B To change the contract's address

C To provide information about the function's result

D To increase transaction fees

Return values provide information about what the function did or found.

Explain what a return value is in a blockchain smart contract and why it matters.

Think about how a function tells you what it did.

Describe how returning multiple values from a smart contract function works and when you might use it.

Consider a function that needs to send back more than one piece of information.