Unit 3: Introduction to Truffle and smart contracts development - Practice Quiz

1 What is Truffle primarily used for in blockchain development?

2 Which programming language is Truffle itself built on and run with?

3 Which command is commonly used to install Truffle globally?

4 In a Truffle project, which configuration file stores network and compiler settings?

5 Which Truffle command initializes a new, empty project structure?

6 Which programming language is most commonly used to write Ethereum smart contracts?

7 What is the typical file extension for a Solidity smart contract?

8 Which keyword is used to declare a smart contract in Solidity?

9 Which statement declares the Solidity compiler version in a contract?

10 In which folder of a Truffle project are smart contract source files placed?

11 Which Truffle command compiles the smart contracts in a project?

12 Which Truffle command deploys contracts to a configured network?

13 What is produced when a Solidity contract is compiled?

14 In which folder are the migration scripts stored in a Truffle project?

15 What does ABI stand for in the context of smart contracts?

16 What is the main benefit of using an application template (box) in Truffle?

17 What are reusable Truffle project templates commonly called?

18 Which command is used to download a Truffle Box template into a project?

19 Which blockchain platform is known for being permissioned and enterprise-focused?

20 Which platform is a public blockchain that popularized smart contracts using Solidity?

21 A developer wants a single toolset that handles smart contract compilation, automated testing, and scriptable deployment for Ethereum. Which role does the Truffle framework primarily serve?

22 In a Truffle project, which configuration file is used to define networks, compiler versions, and deployment settings?

23 A team wants a local in-memory blockchain to test contracts quickly without spending real ETH. Which tool in the Truffle ecosystem is designed for this?

24 Which Truffle command would a developer use to scaffold a new project using a predefined Truffle Box template?

25 In which directory of a standard Truffle project should Solidity source files (.sol) be placed?

26 A simple contract begins with pragma solidity ^0.8.0;. What does the caret (^) in the version pragma indicate?

27 Consider a state variable declared as uint256 public count; in a Solidity contract. What does the public keyword automatically provide?

28 A developer writes a function intended to receive Ether directly. Which function modifier must be included for the function to accept ETH?

29 After running truffle compile, where does Truffle place the resulting contract artifacts (ABI and bytecode)?

30 Which command deploys contracts to a configured network by running the scripts in the migrations/ folder?

31 A migration script contains deployer.deploy(MyContract, 100);. What does the value 100 represent?

32 A developer runs truffle migrate a second time without changes and notices contracts are not redeployed. Which flag forces all migrations to run again from the beginning?

33 Why does deploying a smart contract to a public Ethereum network require gas, while compiling it locally does not?

34 What is the primary advantage of starting a dApp from a Truffle Box rather than an empty project?

35 A developer unboxes the react Truffle Box. Which combination of concerns does this template typically address out of the box?

36 When choosing an application template for a new project, which factor is MOST important to evaluate first?

37 An enterprise consortium needs a permissioned blockchain where participant identities are known and controlled. Which platform's templates are most appropriate?

38 Which characteristic distinguishes an ERC-20 token template from an ERC-721 token template?

39 A key difference between Ethereum and Hyperledger Fabric templates is their approach to data visibility. Which statement is correct?

40 On which platform are smart contracts commonly called "chaincode" and written in general-purpose languages like Go or Java?

41 In a Truffle project, a developer sets networks in truffle-config.js with network_id: "*" for the development network. What is the precise consequence of using the wildcard versus a fixed numeric id?

42 A team wants deterministic, repeatable deployments where migration state is persisted on-chain. Which Truffle mechanism records which migrations have already run?

43 Given a Solidity contract with uint8 public counter; incremented in a loop, at what value does an unchecked increment wrap in Solidity versus earlier versions?

44 A contract declares constructor() payable {} and a non-payable function deposit(). A user sends 1 ETH with a call to deposit(). What happens?

45 During truffle compile, the artifact JSON contains both bytecode and deployedBytecode. What is the key difference between them?

46 A deployment fails with "exceeds block gas limit". Which action is most likely to resolve it without changing contract logic?

47 In a migration script, deployer.deploy(A); deployer.deploy(B, A.address); sometimes fails with A.address undefined. What is the correct pattern?

48 A contract compiles cleanly but truffle migrate reverts in the constructor only on a public testnet, not on Ganache. Which cause is most plausible?

49 A developer runs truffle unbox <box>. What does unboxing an application template primarily provide beyond raw contract files?

50 When a Truffle Box ships with a truffle-box.json file, what is its main role during truffle unbox?

51 A team forks a React Truffle Box but their front-end cannot find the deployed contract address after redeploying. What is the most likely fix?

52 Which statement best contrasts a DApp starter template targeting Ethereum with a chaincode template targeting Hyperledger Fabric?

53 A template advertises "upgradeable contracts." Which architectural pattern is almost certainly in use?

54 A token template implements ERC-20 but exposes a mint() callable by anyone. What is the primary security flaw?

55 In Hyperledger Fabric, a chaincode template reads a key, modifies it, and writes it back. Under high concurrency, two transactions in the same block touch the same key. What determines the outcome?

56 An Ethereum template uses tx.origin for authorization. Why is this considered an edge-case vulnerability compared to msg.sender?

57 Which difference most directly explains why a Fabric chaincode cannot rely on Math.random() or system time the way off-chain code might?

58 Two contracts in a project pin different pragma ranges: ^0.8.0 and >=0.7.0 <0.9.0. The config sets compilers.solc.version: "0.8.19". What is the result?

59 In the Truffle console, calling a view function returns a value immediately, but calling a state-changing function returns a transaction object instead of the new state. Why?

60 A contract stores a dynamic string[] public names;. A developer worries about gas when iterating over it in a function to find a match. What is the fundamental risk?