Blockchain CBDE Exam Practice Test Instant Access

Question 1

The following are value types in Solidity.

AInteger, Boolean, Struct, Mapping and Enum.

BInteger, Boolean, Enum and Addresses.

CInteger, Boolean, Structs and Fixed Point Numbers.

Answer : B

Question 2

If you are starting a new ERC20 token:

Ait would be best to start from scratch, just looking at the required interface.

Bit is beneficial to copy and paste the already existing code from the Ethereum wiki and modify this until you like it.

Cbest is to start with an audited implementation, for example from OpenZeppelin, in order to reuse already existing code.

Answer : C

Question 3

Solidity files:

Acan't be split across multiple files, everything should be in one single file.

Bcan be split across multiple files, but every contract must be in a file with the same name as the contract itself.

Ccan be spread across multiple files. To import all contract from a file you can use 'import 'myfile.sol'. To import Contract MyContract from myfile.sol you use 'import {MyContract as SomeContract} from 'myfile.sol';'.

Answer : C

Question 4

If you need more fine-grained functionality than solidity offers out of the box:

Ayou can incorporate inline-assembly to get better controls.

Byou have to import pre-compiled assembly files which are then hard-copied into the bytecode of the compiled solidity file.

Cyou can use Viper, the experimental assembly like language specifically to offer more flexibility.

Answer : A

Question 5

Transactions containing the same data to create the same smart contract are:

Aalways having the same signature.

Bhaving a different signature because of the nonce which changes upon every transaction.

Answer : B

Question 6

When a new block is mined:

Aa list of transactions as well as uncles is incorporated in the block. All gas that is used during those transactions is added to the miners' balance. Also, the block reward is added to the miner. Then the same transactions are run again by every participating node in the network to achieve consensus.

Ba list of transactions is incorporated in that block. Gas used during the execution is attached to the executing contracts while the block reward is automatically spread across the mining pool to ensure a fair spread. Consensus is reached by a special form of hash code.

Answer : A

Question 7

Public Keys vs. Private Keys. Which statement is true?

AThe Public Key is for Signing Transactions, the Private Key must be given out to verify the signature.

BThe Private Key signs transactions, the Public Key can verify the signature.

CThe Private Key is to generate a Public Key. The Public Key can sign transactions, the address is here to verify the transactions.

Answer : B

Blockchain BTA Certified Blockchain Developer - Ethereum CBDE Exam Practice Test