pragma solidity ^0.5.12;
contract PropertyTransferApp {
    address public contractOwner;
    constructor() public {
        contractOwner = msg.sender;
    }
    modifier onlyOwner() {
        require(msg.sender == contractOwner);
        _;
    }
    struct Property {
        uint256 id;
        string name;
        string owner;
        uint256 value;
        uint256 area;
    }
mapping(uint256 => Property) public properties;
    function addProperty(
        uint256 _propertyid,
        string memory _name,
        string memory _owner,
        uint256 _value,
        uint256 _area
    ) public onlyOwner {
        properties[_propertyid].name = _name;
        properties[_propertyid].owner = _owner;
        properties[_propertyid].value = _value;
        properties[_propertyid].area = _area;
    }
function queryPropertyById(uint256 _propertyid)
        public view returns (
            string memory name,
            string memory owner,
            uint256 area,
            uint256 value
        )
    {
        return (
            properties[_propertyid].name,
            properties[_propertyid].owner,
            properties[_propertyid].area,
            properties[_propertyid].value
        );
    }
function transferPropertyOwnership(
        uint256 _propertyid,
        string memory _newOwner) public {
        properties[_propertyid].owner = _newOwner;
    }
}