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hw1/src/NFinTech/NFinTech.sol

@@ -75,30 +75,52 @@ contract NFinTech is IERC721 {
     }
 
     function setApprovalForAll(address operator, bool approved) external {
-        // TODO: please add your implementaiton here
+        require(operator != address(0), "ERC721: setting approve to the zero address");
+        require(msg.sender != operator, "ERC721: setting approval status for self");
+
+        _operatorApproval[msg.sender][operator] = approved;
+        emit ApprovalForAll(msg.sender, operator, approved);
     }
 
     function isApprovedForAll(address owner, address operator) public view returns (bool) {
-        // TODO: please add your implementaiton here
+         return _operatorApproval[owner][operator];
     }
 
     function approve(address to, uint256 tokenId) external {
-        // TODO: please add your implementaiton here
+        address owner = _owner[tokenId];
+        require(owner == msg.sender || isApprovedForAll(owner, msg.sender), "ERC721: approve caller is not owner nor approved for all");
+        require(owner != address(0), "ERC721: approval to non-existent token");
+
+        _tokenApproval[tokenId] = to;
+        emit Approval(owner, to, tokenId);
     }
 
     function getApproved(uint256 tokenId) public view returns (address operator) {
-        // TODO: please add your implementaiton here
+        require(_owner[tokenId] != address(0), "ERC721: approved query for nonexistent token");
+        return _tokenApproval[tokenId];
     }
 
     function transferFrom(address from, address to, uint256 tokenId) public {
-        // TODO: please add your implementaiton here
-    }
+        require(_owner[tokenId] == from, "ERC721: transfer of token that is not own");
+        require(to != address(0), "ERC721: transfer to the zero address");
+        require(msg.sender == from || getApproved(tokenId) == msg.sender || isApprovedForAll(from, msg.sender), "ERC721: transfer caller is not owner nor approved");
+
+        // 清除之前的授权
+        _tokenApproval[tokenId] = address(0);
+
+        _balances[from] -= 1;
+        _balances[to] += 1;
+        _owner[tokenId] = to;
+
+        emit Transfer(from, to, tokenId);
+        }
 
     function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) public {
-        // TODO: please add your implementaiton here
+       transferFrom(from, to, tokenId);
     }
 
     function safeTransferFrom(address from, address to, uint256 tokenId) public {
-        // TODO: please add your implementaiton here
-    }
+        safeTransferFrom(from, to, tokenId, "");
+        }
+
 }