Contract Lifecycle: Design, Development, and Deployment BDC Practice Questions (Page 7)

Questions 31–35

1. 31foundation · easy

   Which design principle helps reduce the risk of reentrancy attacks in a smart contract?

   • AUsing the latest compiler version to automatically fix all known vulnerabilities.
   • BAvoiding the use of modifiers to keep the code simple and reduce complexity.
   • CMaking all functions public to increase transparency and allow anyone to call them.
   • DUsing the Checks-Effects-Interactions pattern to update state before making external calls.
   Reveal Solution Discussion Select an answer first
2. 32application · medium

   A team is designing a smart contract for a decentralized exchange that will hold user funds. They want to minimize the risk of a vulnerability being exploited after deployment. Which design principle is most important to apply?

   • AUse a proxy pattern to allow upgradeable logic.
   • BUse a high gas limit for all functions.
   • CKeep the contract logic simple and minimize external calls.
   • DStore all data in a single large contract to reduce deployment cost.
   Reveal Solution Discussion Select an answer first
4. 33foundation · easy

   What is the primary purpose of using a framework like Truffle or Hardhat in Solidity development?

   • ATo automatically audit smart contracts for security vulnerabilities.
   • BTo provide a structured environment for compiling, testing, and deploying smart contracts.
   • CTo replace the need for a local Ethereum node when interacting with the mainnet.
   • DTo generate the bytecode for the Ethereum Virtual Machine without using a compiler.
   Reveal Solution Discussion Select an answer first
5. 34expert · hard

   A developer has deployed an upgradeable proxy contract and verified the logic contract on Etherscan. Users are reporting that they cannot see the proxy's functions on Etherscan. What is the most likely cause and solution?

   • AThe logic contract is not verified; the developer should re-verify the logic contract
   • BThe proxy contract itself has not been verified; the developer should verify the proxy contract with the proxy's ABI and implementation address
   • CThe proxy contract has no ABI; the developer should generate an ABI from the bytecode
   • DThe proxy is using delegatecall, which Etherscan cannot display
   Reveal Solution Discussion Select an answer first
6. 35foundation · easy

   Which testing framework is commonly used with Hardhat to write and run unit tests for smart contracts?

   • ATruffle Test
   • BSelenium
   • CJest
   • DMocha
   Reveal Solution Discussion Select an answer first