一道题回顾智能合约 Coverage

pragma solidity ^ 0.4 .24;
contract Hash {

    bytes32 question = "";
    struct Game {
        bytes32 slogan;
        address owner;
        uint96 times;
        address player;
        bool ready;

    }
    Game game;


    modifier onlyOwner() {
        require(msg.sender == game.owner, "Illegal user!");
        _;
    }

    modifier onlyPlayer() {
        require(msg.sender == game.player, "Illegal user!");
        _;
    }

    constructor(string hash) public {
        question = keccak(hash);
        game.slogan = "Welcome to imagin's Hash World!";
        game.owner = msg.sender;

    }

    function getFlag() view public returns(bool) {
        return (game.times == 43856731668828204536206669571);
    }


    function play() public {
        require(game.player == address(0), "Have been played!");
        game.player = address(msg.sender);

    }

    function guessHash(string answer) public onlyPlayer payable returns(string) {
        game.player = msg.sender;
        require(msg.value > 0.1 ether, "Get yourself rich first.");
        require(game.ready);
        game.ready = false;
        require(isMan(), "You should be real man.");
        if (keccak(answer) == question) {
            game.times++;
            return "Congratulations, you're right~";
        } else {
            game.times--;
            return "Oops, you lost your chance (-1s).";
        }

    }

    function changeSlogen(bytes32 slogan) public {
        Game a;
        a.slogan = slogan;
        game = a;
    }

    function nextHash(string hash) public onlyOwner {
        question = keccak256(hash);
        game.ready = true;
    }

    function keccak(string str) internal pure returns(bytes32) {
        return keccak256(str);
    }


    function getSlogan() view public returns(bytes32) {
        return game.slogan;
    }

    function isMan() internal view returns(bool) {
        uint size;
        assembly { size: = extcodesize(caller) }
        return (size == 0);
    }

    // 方便调试，原题目以下函数不存在

    function getquestion() view public returns(bytes32) {
        return question;
    }

    function getTime() view public returns(uint96) {
        return game.times;
    }

    function getOwner() view public returns(address) {
        return game.owner;
    }

}

function guessHash(string answer) public onlyPlayer payable returns(string) {
    game.player = msg.sender;
    require(msg.value > 0.1 ether, "Get yourself rich first.");
    require(game.ready);
    game.ready = false;
    require(isMan(), "You should be real man.");
    if (keccak(answer) == question) {
        game.times++;
        return "Congratulations, you're right~";
    } else {
        game.times--;
        return "Oops, you lost your chance (-1s).";
    }

}