28-Solidity8.0-待办事件列表

源码：

pragma solidity ^0.8.7;

contract TodoList {
    struct Todo {
        string text;
        bool completed;
    }

    Todo[] public todos;

    function create(string calldata _text) external {
        todos.push(Todo({
            text: _text,
            completed: false
        })
        );
    }

    function updateText(uint _index, string calldata _text) external {
        todos[_index].text = _text;

        //把结构体装到storage中，两种方式消耗的gas费不同，更新的数据少，上面的gas消耗少，更新数据的，下面方法消耗gas少
        Todo storage todo = todos[_index];
        todo.text = _text;
    }

    function get(uint _index) external view returns (string memory, bool) {
        // storage -29397
        // memory -29480
        Todo memory todo = todos[_index];
        return(todo.text, todo.completed);
    }

    function toggleCompleted(uint _index) external {
        todos[_index].completed = !todos[_index].completed;
    }
}