DeclarationError : undeclared identifier

Question

我正在为彩票项目编写智能合约。这是其中一行导致错误的函数！

function WinnerOfLottery() public view returns(address){
        require(msg.sender==manager);
        require(participants.length >=3);
        **uint r=random();**
        address payable winner;
        uint randIndex = r % participants.length;
        winner= participants[randIndex];
        return winner;
    }

Answer 1

错误在函数的声明中，我制作了用于生成随机获胜者的函数