Solidity Basic Solidity (Web Dev) 5

Question 1

What is the result of integer overflow in Solidity 0.8.0 and later?

Accepted Answer

The transaction reverts automatically

Answer

Solidity 0.8+ includes built-in overflow/underflow checks that revert the transaction on overflow.

Question 2

Which function selector is called when Ether is sent to a contract with no calldata and no fallback?

Accepted Answer

The receive() function

Answer

The receive() function, if defined and marked payable, handles plain Ether transfers with no calldata.

Question 3

In Solidity, what is 'calldata' as a data location?

Accepted Answer

Read-only non-persistent data location for external function input parameters

Answer

Calldata is a read-only, non-persistent area where external function arguments are stored, cheaper than memory.

Question 4

What does the Solidity 'interface' keyword enforce that 'abstract contract' does not?

Accepted Answer

Interfaces cannot have any implementation; all functions must be external and unimplemented

Answer

Interfaces only allow external function declarations with no implementation, no state variables, and no constructors.

Question 5

What is the gas cost implication of using 'storage' vs 'memory' for arrays in Solidity?

Accepted Answer

Storage reads/writes cost significantly more gas than memory operations

Answer

Storage operations (SLOAD/SSTORE) are among the most expensive EVM opcodes, far costlier than memory operations.

Solidity Practice Test