Solidity Basic Solidity (Web Dev) 2

Question 1

Which keyword is used to declare a function that cannot modify contract state in Solidity?

Accepted Answer

view

Answer

The 'view' keyword declares a function that reads but does not modify contract state.

Question 2

What does the 'payable' modifier on a function allow in Solidity?

Accepted Answer

The function can receive Ether

Answer

The 'payable' modifier allows a function to receive Ether sent along with the call.

Question 3

Which of the following is the correct way to declare a mapping from address to uint in Solidity?

Accepted Answer

mapping(address => uint) balances;

Answer

Solidity mappings use the syntax 'mapping(KeyType => ValueType) variableName'.

Question 4

What is the default visibility of state variables in Solidity?

Accepted Answer

internal

Answer

State variables default to 'internal' visibility if no modifier is specified.

Question 5

Which Solidity data type stores a sequence of bytes of fixed size up to 32?

Accepted Answer

bytesN (e.g. bytes32)

Answer

Fixed-size byte arrays like bytes1 through bytes32 store a fixed number of bytes efficiently.

Solidity Practice Test