當我們需要一個學生的類別時，原生的 type 並不能滿足我們，這時候就到了 struct 出場啦！他能幫助我們自己定義所需要的 type 。

本日合約:

pragma solidity ^0.4.25;
contract Class {
    struct Student {
        string name;
        uint score;
        bool active;
    }
    mapping(uint => Student) students;
    
    modifier ActiveStudent(uint id) {
        require(students[id].active, "Student is inactive");
        _;
    }
    
    function register(uint id, string name) public {
        students[id] = Student({name: name, score: 0, active: true});
    }
    
    function modifyScore(uint id, uint score) public ActiveStudent(id) {
        students[id].score = score;
    }
    
    function getStudent(uint id) public ActiveStudent(id) view returns (string, uint) {
        return (students[id].name, students[id].score);
    }
}

本日影片:
https://youtu.be/62I86dgVc2g

Smart Contract 實戰教學播放清單：
https://www.youtube.com/playlist?list=PLHmOMPRfmOxSJcrlwyandWYiuP9ZAMYoF