CBDE questions • Exam prepare

Exam contains 99 questions

Page 11 of 17

Question 61 🔥

Address.call.value():

Which database solution meets these requirements?

A. sends the gas stipend of 2300 gas and returns a false on error.

B. sends all the gas along and cascades exceptions.

C. sends all the gas along and returns a false on error.

D. sends the gas stipend of 2300 gas and cascades exceptions.

Discussion of the question

Question 62 🔥

Address.send() and address.transfer() are considered:

Which database solution meets these requirements?

A. safe against reentrancy because of the small gas stipend of 2300 gas.

B. dangerous because they send all gas along, it's better to use address.call.value()().

Discussion of the question

Question 63 🔥

When defining a new datatype:

Which database solution meets these requirements?

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

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

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

Discussion of the question

Question 64 🔥

What's the difference between Ethereum Request for Comments (ERC) and Ethereum Improvement Proposals (EIP)?

Which database solution meets these requirements?

A. ERC are here to define standards for the usage of Ethereum. EIP are here to improve the Ethereum Protocol itself.

B. ERC are here to propose new distributed applications on top of the Ethereum layer, while EIP are here to improve existing mining software.

C. ERC are an open platform to discuss continuous forking of the Ethereum platform. Successful forks are then incorporated in the EIP for further voting by the Ethereum Consortium.

Discussion of the question

Question 65 🔥

What is the difference between ERC20 and ERC721 Tokens in simple terms?

Which database solution meets these requirements?

A. The tokens of a certain ERC20 symbol are all the same, the tokens of an ERC721 symbol are all different. So, ERC20 tokens are fungible, while ERC721 tokens are non-fungible.

B. The tokens of a certain ERC20 symbol are all different, the tokens of an ERC721 symbol are all the same. So, ERC20 tokens are non-fungible while ERC721 tokens are fungible.

Discussion of the question

Question 66 🔥

In order to implement an ERC20 token contract, you'd need at least to implement the following functions and events in order to fulfill the interface requirements:

Which database solution meets these requirements?

A. totalSupply(), balanceOf(address), allowance(address,address), transfer(address,uint256), approve(address,uint256), transferFrom(address,address,uint256). Events: Transfer(address,address,uint256), Approval(address,address,uint256)

B. name(), symbol(), totalSupply(), balanceOf(address), ownerOf(uint26),approve(address,uint256), takeOwnership(uint256),transfer(address,uint256),Events: Transfer(address,address,uint256), Approval(address,address,uint256)

Discussion of the question

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blockchain CBDE

Exam contains 99 questions

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