CBDE by Blockchain Actual Free Exam Q&As

Question 1

The following are value types in Solidity.

A. Integer, Boolean, Enum and Addresses. B. Integer, Boolean, Structs and Fixed Point Numbers. C. Integer, Boolean, Struct, Mapping and Enum.

Discussion 0

Correct Answer: A Vote an answer

Question 2

Having a bug-bounty program early on:

A. is completely useless. Who wants to test beta-ware software? It's better to start with the bug-bounty program after the contract is released on the main-net. B. might be a burden as it is an administrative overhead mainly. C. can help to engage the community in testing your smart contracts and therefore help to find bugs early.

Discussion 0

Correct Answer: C Vote an answer

Question 3

Inheritance is useful, because a contract that is derived from another contract can make use of:

A. all public state variables and properties, public and internal functions and modifiers. B. all public and private state variables, public, internal and external functions, but not modifiers C. all public state variables and properties, public functions and modifiers, but not internal, external or private ones.

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Correct Answer: A Vote an answer

Question 4

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

A. having a different signature because of the nonce which changes upon every transaction. B. always having the same signature.

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Correct Answer: A Vote an answer

Question 5

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

A. with private state variables. This way nobody else other than the smart contract itself can see the information B. with 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. C. You 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.

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Correct Answer: C Vote an answer

Question 6

Proof of Work (PoW) vs. Proof of Stake.

A. PoS is mining with specialized new hardware that has to be purchased with a stack of Ether in the network. Hence the Name: Proof of Stake, which derives from Stack. B. PoW is computationally intensive which requires lots of energy. On the other hand, miners earn straightforward a reward for mining a block and incorporating transactions. C. PoW is better than PoS, because with PoS we increase the amount of energy spent on the network.

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Correct Answer: B Vote an answer

Blockchain BTA Certified Blockchain Developer - Ethereum - CBDE Exam Practice Test