Question

我曾尝试通过编译器版本0.5.12编译此代码，但我有一个例外：

浏览器/无标题。sol：21：24：DeclarationError：标识符未找到或不唯一。

函数getRoleOf（地址广告）公共返回（字符串txt）{

^ ---- ^

我的代码：

pragma solidity >=0.4.22 <0.5.13;
contract Max{
    mapping(address => uint256) private balaces;
    mapping(address => role) private roles;
    enum role{
        Admin,
        Manager,
        User
    }

    constructor() public{
        balaces[msg.sender] = 1000;
        roles[msg.sender] = role.Admin;
    }

    function getRoleOf(adress ad) public returns(string txt){
        if(roles[ad] == role.User){
            txt = "User";
            return;
        }
        if(roles[ad] == role.Manager){
            txt = "Manager";
            return;
        }
        if(roles[ad] == role.Admin){
            txt = "Admin";
            return;
        }
        return "Нет такого пользователя";
    }
}

我的代码有什么问题？

Answer 1

上面的答案（@abcoathup提供）适用于0.4.26，如果您想在实体版本0.5.12中执行代码，请检查以下代码（稍作优化）

pragma solidity >=0.4.22 <0.5.13;
contract Max{
    mapping(address => uint256) private balaces;
    mapping(address => role) private roles;
    enum role{
        Admin,
        Manager,
        User
    }

    constructor() public{
        balaces[msg.sender] = 1000;
        roles[msg.sender] = role.Admin;
    }

    function getRoleOf(address ad) public returns(string memory txt){
        txt = "Нет такого пользователя";
        if(roles[ad] == role.User){
            txt = "User";
        } else if(roles[ad] == role.Manager){
            txt = "Manager";
        } else if(roles[ad] == role.Admin){
            txt = "Admin";
        }
        return txt;
    }
}

Answer 2

：function getRoleOf(adress ad)中有一个错字 adress应该是address

以下使用Solidity Compiler 0.4.26在Remix中进行编译

pragma solidity >=0.4.22 <0.5.13;
contract Max{
    mapping(address => uint256) private balaces;
    mapping(address => role) private roles;
    enum role{
        Admin,
        Manager,
        User
    }

    constructor() public{
        balaces[msg.sender] = 1000;
        roles[msg.sender] = role.Admin;
    }

    function getRoleOf(address ad) public returns(string txt){
        if(roles[ad] == role.User){
            txt = "User";
            return;
        }
        if(roles[ad] == role.Manager){
            txt = "Manager";
            return;
        }
        if(roles[ad] == role.Admin){
            txt = "Admin";
            return;
        }
        return "Нет такого пользователя";
    }
}

Answer 3

pragma solidity ^0.8.0;

导入“https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol”；

合约 BlackLivesMatterToken 是 ERC20 { 构造函数（unit256 initialSupply）公共ERC20（“BlackLivesMatterToken”，“BLM”）{ _mint(msg.sender, initialSupply); } }

稳定-错误：找不到标识符或标识符不唯一。编译错误

3 个答案: