feat(nft-market): add getAllListings function and update README

Implement a new function `getAllListings` in the NFTMarket contract to allow
外部调用者获取所有上市的信息。此外, 更新了README以反映新的合约地址。

members/veithly/task3/NFTMarket.sol

@@ -1,4 +1,5 @@
-pragma solidity ^0.8.0;
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
 
 import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
 import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
@@ -19,7 +20,7 @@ contract NFTMarket is Ownable {
     event NFTListed(uint256 listingId, address seller, address nftContract, uint256 tokenId, uint256 price);
     event NFTBought(uint256 listingId, address buyer);
 
-    constructor(address _currencyToken) {
+    constructor(address _currencyToken) Ownable(msg.sender) {
         currencyToken = IERC20(_currencyToken);
     }
 
@@ -45,4 +46,13 @@ contract NFTMarket is Ownable {
 
         emit NFTBought(_listingId, msg.sender);
     }
-}
+
+
+    function getAllListings() external view returns (Listing[] memory) {
+        Listing[] memory allListings = new Listing[](listingCount);
+        for (uint256 i = 1; i <= listingCount; i++) {
+            allListings[i-1] = listings[i];
+        }
+        return allListings;
+    }
+}

members/veithly/task3/README.md

@@ -1,2 +1,2 @@
-List NFT: 0x9a659e39b29263ef2817c26a359e299580c1027982a27658dc486546adfa1097
-Buy NFT: 0x0b2f69f185a4936410509a1c16b8f5f5e5c0734ead93b871486cd00a7254d8a2
+List NFT: 0xf563a73569698f80a82eab21e4ba4eaf5c73db5e85a398f03e7fa5aef2ca5e35
+Buy NFT: 0x7948cece92264265a0008d458f18f7f421036f95982082f1908ea712abf4a50d