Ethereum Developer Test 4

Question 1

Which is TRUE about Events?

Accepted Answer

Cannot be accessible by contracts because they are stored in a side-chain or similar structure.

Answer

When a contract contacts another contract, they a) Are stored on chain and provide a wonderful way to receive a return value.

Answer

Are mostly employed in Solidity for debugging exceptions.

Question 2

Which network node is not PoW?

Accepted Answer

Rinkeby

Answer

Morden

Answer

Olympic

Answer

Ropsten

Question 3

Solidity has the following value types.

Accepted Answer

Addresses, Integer, Boolean, and Enum

Answer

Fixed Point Numbers, Integers, Booleans, and Structures

Answer

Solidity has the following value kinds.

Question 4

Variables of the type address hold

Accepted Answer

A value of 20 bytes

Answer

A string

Answer

A value of 32 bytes

Answer

A 20-character hexadecimal number

Question 5

A version pragma is a great method

Accepted Answer

To identify the compiler version for which a smart contract was created. Keeping changes from breaking helps.

Answer

To identify the blockchain for which a smart contract was created. It aids in avoiding misunderstandings with beta users.

Answer

To identify the blockchain node for which a smart contract was created. It is beneficial to avoid combining various Go-Ethereum iterations.

Question 6

What was the name of Teku's eth2 client prior to their rebranding?

Accepted Answer

Artemis

Answer

Apollo

Answer

Poseidon

Answer

Zeus

Question 7

Which is TRUE about Loops in Solidity?

Accepted Answer

Are risky when employed with expanding data structures, like arrays or mapping, because it is difficult to predict the gas requirements

Answer

Should be avoided as much as possible due to potential negative impact on gas requirements.

Answer

Are an excellent approach to get around the need for gas because a loop only uses gas once.

Question 8

Which is TRUE when defining a new datatype?

Accepted Answer

Using a struct is preferable because it is less expensive than launching a new contract.

Answer

Solidity does not support the creation of new datatypes.

Answer

A contract with public storage variables is recommended since it can be utilized like a class.

Question 9

The result of the division of two integers, 5/2, is

Accepted Answer

2, as the decimal point has been truncated.

Answer

.5, as it is instantly transformed into a float.

Answer

3, as it is always rounded

Answer

None of the above.

Question 10

As per the official Style Guide,

Accepted Answer

Functions should use mixedCase, while contract names should be capitalized. You should indent text with four spaces and limit lines to 79 (or 99) characters.

Answer

Both the function names and the contract should be in mixed case. It is proper to capitalize events. There should be a maximum of 120 characters per line and 2 spaces used as indentation.

Answer

To avoid misunderstanding with JavaScript, you should capitalize function names, events, and contract names. To indent, use Tabs, and keep lines to a maximum of 80 characters.