Ethereum Virtual Machine BDC Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A developer is explaining the EVM to a colleague. They state that the EVM is a stack-based machine. What does this mean for smart contract execution?

   • AAll data is stored in a stack, and memory is not used.
   • BOperations are performed on a last-in-first-out stack of 256-bit words.
   • CThe stack is the only persistent storage available.
   • DThe stack size is unlimited, allowing complex computations.
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2. 2expert · hard

   A developer is deploying a contract that has a constructor which performs a complex initialization. The deployment transaction is sent with a gas limit that is exactly the amount needed for the constructor. After the constructor completes, the contract's runtime code is stored. What happens to the gas that was used to execute the constructor?

   • AIt is burned as part of the deployment cost.
   • BIt is transferred to the new contract's balance.
   • CIt is included in the total gas cost of the deployment transaction.
   • DIt is refunded to the sender after deployment.
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4. 3application · medium

   A developer is deploying a new smart contract to the Ethereum mainnet. The contract's constructor performs several storage writes. The deployment transaction runs out of gas and reverts. What is the state of the contract after this failed deployment?

   • AThe contract is deployed, but its storage is empty.
   • BThe contract is not deployed, and all state changes are rolled back.
   • CThe contract is deployed but with partial state.
   • DThe contract is deployed, but only the constructor's storage writes are reverted.
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5. 4application · medium

   A developer is writing a low-level assembly routine in Solidity using inline assembly. The routine needs to copy a 32-byte value from a specific memory location to the top of the stack. Which sequence of opcodes should be used?

   • APUSH1 <memory_offset>, MSTORE
   • BPUSH1 0x00, MLOAD
   • CPUSH1 <memory_offset>, SLOAD
   • DPUSH1 <memory_offset>, MLOAD
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6. 5application · medium

   A smart contract function transfers tokens to a recipient and then updates a balance mapping. The function is called by a user. If the transfer fails due to insufficient balance, what is the state of the contract after the transaction?

   • AThe balance mapping is updated, but the token transfer is skipped.
   • BThe entire transaction is reverted, and all state changes are rolled back.
   • CThe contract enters a paused state and requires manual intervention.
   • DThe transfer is reverted, but the balance mapping update persists.
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