최신Blockchain BTA Certified Blockchain Developer - Ethereum - CBDE무료샘플문제

A. the Value can be anything, but the key cannot be another mapping, struct, integer or Boolean.

B. the value can be anything, but the key cannot be another mapping, struct, enum or dynamically sized array.

C. the Keys can be anything, but the value can't be another mapping or struct.

A. it's best to use a struct, which is cheaper than deploying a new contract.

B. it's not possible to generate new datatypes in Solidity.

C. its best to use a contract with public storage variables, so it can be used like a class.

A. for Java, JavaScript, and C++

B. for JavaScript using Web3.js

C. for Solidity and JavaScript

D. for any language, as long as it adheres to the open Testing-Interface from Truffle

A. to check input arguments from users.

B. to check internal states that should never happen.

A. PoW is better than PoS, because with PoS we increase the amount of energy spent on the network.

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. 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.

A. would be worse, because it would increase the amount of energy needed for mining.

B. would be better, because it can reduce the amount of energy needed for mining.

A. can only be accessed during calls.

B. can be accessed during transactions and calls.

A. contract MyContractA is MyContractB { ... }

B. contract MyContractA extends MyContractB {...}

C. contract MyContractB derives MyContractA {...}

D. contract MyContractA inherit (MyContractB) {...}

A. is not good, because you might give out secrets.

B. is great, because they often find bugs which weren't considered before.