Ethereum Virtual Machine BDC Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A developer is designing a contract that must be deterministic across all nodes. Which of the following operations should be avoided to ensure determinism?

   • AUsing the transaction sender's address in a calculation.
   • BUsing the contract's own address in a calculation.
   • CUsing the block timestamp in a calculation.
   • DUsing the block number in a calculation.
   Reveal Solution Discussion Select an answer first
2. 27expert · hard

   A developer is deploying a contract that uses a selfdestruct function to clean up. They are aware that selfdestruct sends the contract's remaining balance to a specified address. What is a critical consideration when using selfdestruct?

   • AThe contract's balance is sent to the specified address, and the contract is removed from the blockchain.
   • BThe contract's code is removed, but storage remains.
   • CThe contract can be restored by calling it again.
   • DThe contract's storage is automatically migrated to the recipient.
   Reveal Solution Discussion Select an answer first
4. 28expert · hard

   A developer is writing a function that returns a large struct from a smart contract. The struct contains multiple arrays. The developer wants to minimize gas costs for callers. Which approach is most gas-efficient?

   • AReturn the struct by value, which copies it to memory.
   • BReturn a memory pointer to the struct.
   • CReturn individual fields or use a view function to avoid copying the entire struct.
   • DReturn the struct as calldata.
   Reveal Solution Discussion Select an answer first
5. 29foundation · easy

   What happens if a transaction's gas limit is set too low for the operations it needs to execute?

   • AThe transaction is executed but the sender is charged extra gas later
   • BThe transaction is reverted and all state changes are rolled back, but the gas is still consumed
   • CThe transaction is executed partially and the remaining operations are skipped
   • DThe transaction is placed in a queue until the gas price drops
   Reveal Solution Discussion Select an answer first
6. 30foundation · easy

   Which of the following best describes the behavior of an unhandled exception in the EVM?

   • AIt only reverts the current function, leaving other functions' changes intact
   • BIt logs the error and continues execution
   • CIt is caught by the calling contract and execution continues
   • DIt causes the entire transaction to revert, including all state changes
   Reveal Solution Discussion Select an answer first