Solidity Solidity Data Types and Storage

Question 1

Which of the following is a value type in Solidity?

Accepted Answer

uint256

Answer

uint256 is a value type stored directly on the stack, while bytes, string, and mapping are reference types.

Question 2

What is the default value of an uninitialized bool state variable in Solidity?

Accepted Answer

false

Answer

In Solidity, all uninitialized state variables are set to their zero value; for bool that is false.

Question 3

What is the maximum value that can be stored in a uint8 in Solidity?

Accepted Answer

255

Answer

uint8 is an 8-bit unsigned integer, so its maximum value is 2^8 - 1 = 255.

Question 4

Which Solidity type correctly declares a fixed-size byte array of exactly 32 bytes?

Accepted Answer

bytes32

Answer

bytes32 is Solidity's built-in fixed-size byte array type that holds exactly 32 bytes.

Question 5

What is the key difference between int256 and uint256 in Solidity?

Accepted Answer

int256 can store negative values while uint256 cannot

Answer

int256 is a signed integer that can hold both positive and negative values, while uint256 is unsigned and only holds non-negative values.

Solidity Practice Test