Blockchain CBDE Exam Questions Instant Access

Question 1

All low-level functions on the address, so address.send(), address.call.valueQQ, address.callcode and address.delegatecall:

Aare interrupting execution on error, because they throw an exception.

Bcontinuing execution on error silently, which is the reason why they are so dangerous.

Creturning Booleans to indicate an error during execution.

D.send() throws an exception, while the other functions are returning Booleans during execution to indicate an error.

Answer : C

Question 2

When you are programming a game like poker of battleships where you need to hide opponents values is:

Awith private state variables. This way nobody else other than the smart contract itself can see the information

Bwith external contracts holding those values. This way we can make sure that the information flow is following a clear logic and nobody else can access this information.

CYou can't hide anything on the blockchain, because the information is public, just the call is private which means only other smart contracts would be limited in accessing that information.

Answer : C

Question 3

You need to use ____________ to get the address that initiated the transaction.

ATx.origin

BMsg.sender

Answer : A

Question 4

To avoid issues during Ethereum platform upgrades:

Ait's good to inform users about the updates via a newsletter.

Bit's good to have the ability to pause a contract in order to manage the money at risk.

CEthereum doesn't upgrade the platform. It's fixed and final.

Answer : B

Question 5

Hashing Mining uses:

AKeccack256 while internally to hash values it's easy to use the Dagger-Hashimoto to create a meaningful hash.

Bthe Dagger-Hashimoto hashing while internally the EVM uses SHA256 which is an alias for Keccack256.

Cthe Dagger-Hashimoto hashing while internally the EVM uses Keccack256 which is almost similar to SHA256, but has a different padding so produces different hashes.

Answer : C

Question 6

Truffle boxes are a great way:

Ato contribute to the box community which is the distributed file system for truffle.

Bto start with a pre-configured environment for most web-development needs.

Cto use tools that makes boxing of Dapps for different platforms very easy.

Answer : B

Question 7

Sending one Ether is actually internally translated:

Ato Wei, so it will send the equivalent of 10^18 Wei.

Bto Finney, so it will send the equivalent of 10^3 Finney.

Cto Szabo, so it will send the equivalent of 10^6 Szabo.

Answer : A

Blockchain BTA Certified Blockchain Developer - Ethereum CBDE Exam Questions