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Practical Exam BPDA

Date: 5 February 2024
Duration: 60 minutes

1. Instructions​

  • You have 60 minutes for this practical exam.
  • You can access any non-collaborative resource including:
  • You can solve the tasks on any blockchain you want (e.g., MultiversX, Ethereum, Solana).
  • You can solve the tasks in any order.
  • Total Points: 110p (100p will get you the maximum grade).

Teacher Addresses​

  • MultiversX: erd1ld6er5zpdze3cynzkapur9qhzh826jje6n87g7tvdftszs8jn2qv44nqd
  • Ethereum: 0x8270685220fAd7EDb232E649EeE9D8810dac1d58

2. Wallet Setup​

Create a wallet on testnet/devnet and use it to solve the following tasks. Call the Faucet to get tokens.

3. Issue an NFT Collection (25p)​

  1. Issue the collection (15p):
    • Token Name: BPDAExamNFT
    • Token Ticker: BPDANFT
  2. Create an NFT (10p):
    • Based on the issued collection, create an NFT.
    • Set the royalties to 7%.
    • Send the NFT to the $TEACHER_ADDR.

4. Issue a Fungible Token (35p)​

  1. Issue the token (20p):
    • Token Name: BPDAExamFT
    • Token Ticker: BPDA
    • Initial supply: 1991 tokens
    • Number of decimals: 18
  2. Mint additional tokens (5p):
    • Mint an additional 9 tokens.
  3. Transfer (10p):
    • Send 500 tokens to the $TEACHER_ADDR.

5. Token Marketplace Smart Contract (70p)​

Write a smart contract for a Token Marketplace. The smart contract should allow users to list, buy, and sell fungible or non-fungible tokens.

a. Token Listing (25p)​

Users can list their tokens for sale by specifying:

  • Token type (Fungible or NFT).
  • Token identifier.
  • Quantity (for fungible tokens).
  • Price per token.

Endpoints:

  1. listToken: Allows a user to list their token for sale.
    • Inputs: tokenId, quantity, price.
  2. removeListing: Allows the seller to remove their listing.
    • Inputs: listingId.
  3. getListings: Returns all active token listings.
  4. getMyListings: Returns all token listings created by the current user.

b. Token Purchase (25p)​

Buyers can purchase tokens by sending the specified amount in the blockchain's native currency (e.g., EGLD, ETH). Ensure proper fund transfer and ownership update.

Endpoints:

  1. buyToken: Allows a user to buy a token by specifying the listing ID and quantity (if applicable).
    • Inputs: listingId, quantity.
  2. getPurchasedTokens: Returns the list of tokens purchased by the user.

c. Events (20p)​

Define corresponding events for transparency and notifications:

  1. TokenListed – Emitted when a token is listed for sale.
  2. TokenPurchased – Emitted when a token is successfully purchased.
  3. ListingRemoved – Emitted when a token listing is removed.
  4. AuctionCreated – (Optional) Emitted when an auction is created.
  5. BidPlaced – (Optional) Emitted when a bid is placed.
  6. AuctionEnded – (Optional) Emitted when an auction ends successfully.