Solidity Solidity Data Types and Storage 3

Question 1

What is the primary advantage of using calldata over memory for external function parameters in Solidity?

Accepted Answer

calldata is read-only and avoids an extra copy, making it more gas-efficient

Answer

calldata allows modifying the input data

Answer

calldata is permanent and persists after the call

Answer

calldata supports nested dynamic types that memory does not

Question 2

How many EVM storage slots does a single uint256 state variable occupy?

Accepted Answer

1 slot

Answer

8 slots

Answer

4 slots

Answer

2 slots

Question 3

Which combination of variables can be packed together into a single 32-byte EVM storage slot?

Accepted Answer

A uint128 and a uint128

Answer

Two uint256 variables

Answer

A uint256 and a uint128

Answer

Three uint256 variables

Question 4

What happens when you assign a storage struct to a local variable without the 'memory' keyword in Solidity?

Accepted Answer

A storage pointer (reference) to the original is created

Answer

A copy is created in memory

Answer

The value is copied to calldata

Answer

The compiler throws an error

Question 5

What storage slot number is assigned to the first state variable declared in a Solidity contract?

Accepted Answer

Slot 0

Answer

Slot 1

Answer

Slot 2

Answer

Depends on the variable type

Question 6

Which data location is most gas-efficient for read-only external function parameters of reference types?

Accepted Answer

calldata

Answer

memory

Answer

storage

Answer

stack

Question 7

What happens to variables stored in the memory data location after a Solidity function call ends?

Accepted Answer

They are erased and the memory is freed

Answer

They are stored permanently in the contract's storage

Answer

They are moved to calldata for the next call

Answer

They persist until the next transaction is mined