Blockchain Developer Smart Contract Development Questions and Answers

Question 1

A development team is building a decentralized finance (DeFi) application where security and auditability are the highest priorities.
The contract's logic is straightforward, but it will handle significant financial value.
Which smart contract language would be the most suitable choice based on its design philosophy?

Accepted Answer

Vyper, because it is designed for simplicity, security, and auditability by intentionally limiting complex features.

Answer

Solidity, because of its larger developer community and extensive libraries.

Answer

Yul, because it provides low-level control for gas optimization.

Answer

JavaScript, because of its widespread use in web development and familiar syntax.

Question 2

During a security audit of a smart contract, you discover a function that sends Ether to an external address before updating the contract's internal state that records the sent amount. Which common vulnerability does this pattern introduce?

Accepted Answer

Reentrancy

Answer

Integer Overflow

Answer

Timestamp Dependence

Answer

Denial of Service (DoS)

Question 3

A developer is writing a smart contract function in Solidity that should only read from the blockchain's state but not modify it. Which function visibility keyword is most appropriate and gas-efficient for this purpose when called externally?

Accepted Answer

view

Answer

public

Answer

pure

Answer

internal

Question 4

Which of the following is a critical step that should be performed *before* deploying a smart contract to the mainnet to ensure its security and correctness?

Accepted Answer

Engaging a reputable third-party firm for a comprehensive security audit.

Answer

Purchasing a large amount of the native cryptocurrency to pay for gas fees.

Answer

Announcing the launch date on social media to build hype.

Answer

Registering a domain name for the associated decentralized application (dApp).

Question 5

A developer needs a local blockchain environment for rapid development, testing, and debugging of Ethereum smart contracts. This environment should offer features like stack traces for Solidity, mainnet forking, and a rich plugin ecosystem. Which development framework best fits these requirements?

Accepted Answer

Hardhat

Answer

Remix IDE

Answer

Ganache

Answer

OpenZeppelin

Question 6

To prevent integer overflow and underflow vulnerabilities in Solidity versions prior to 0.8.0, what was the standard best practice?

Accepted Answer

Utilizing the SafeMath library.

Answer

Using `uint256` for all integer operations.

Answer

Wrapping all arithmetic operations in `if` statements.

Answer

Performing all calculations in a separate `private` function.