導言

本次範例以短租為出發點，設計一個短租交易的合約，承租人可以決定一次付清或者每天固定時間支付當日租金，房東只能領取單日租金..(這邊我還要思考一下...)

程式碼

pragma solidity^0.4.25;
contract DailyRentHouse{

    address public Tenant; //承租人
    address public Landlord; //房東
    uint256 public Period; //算天數
    uint256 public DaliyRent; //日租
    uint256 public TotalRent; //總租金
    
    uint256 public AmountPaid; //已付次數
    uint256 public LoadingTime; //下一次付款時間
    
    event Paid(); //record Paid log
    event PaidAll();  //record PaidAll log
    event Received(); //record Received log
    
    
    enum State{
        Creat, //初始
        Paid, //已支付
        Close //已結清
    }
    State public state;
    
    modifier onlyTenant{
        require(msg.sender == Tenant,"你不是承租人");
        _;
    }
    modifier Stage(State _state){
        require(_state == state,"不符合現階段");
        _;
    }
    
    
    constructor(address _tenant, uint256 _daliyRent, uint256 _period) public{
        Landlord = msg.sender;
        Tenant = _tenant;
        Period = _period;
        DaliyRent = _daliyRent;
        TotalRent = _daliyRent * _period;
    }

    
    //每天支付
    function payDaily() public payable onlyTenant{
        require(msg.value == DaliyRent,"支付費用不符合日租費用");
        require(AmountPaid <= Period,"已付清約定租期");
        if(AmountPaid == 0){
            LoadingTime = now + 1 days;
            
        }else{
            require(now >= LoadingTime,"下一次付款時間還沒到");
            LoadingTime = now + 1 days;
        }
        state = State.Paid; //已支付階段
        AmountPaid++; //支付次數
        emit Paid();
    }
    
    //一次付清
    function payAll() public payable onlyTenant{
        require(msg.value == TotalRent,"租金不完整");
        require(AmountPaid <= Period,"已付清約定租期");
        state = State.Paid; 
        AmountPaid = Period; //已付清全部租金
        emit PaidAll();
    }
    

    //房東收取已支付的租金
    function receive() public Stage(State.Paid){
        Landlord.transfer(DaliyRent);
        emit Received();
        if(address(this).balance == 0){
            state = State.Close;
        }
    }
}

解說

(待補)