文章目录 1,原始代码2,运行没问题，但编译会有警告：elaborated-type-specifier for a scoped enum must not use the ‘class’ keyword3,修改 1,原始代码 #include <iostream>enum class TreeType : int {PINE = 1,CYPRESS = 2,WILLOW

create table `grade`(`gradeid` VARCHAR(50) not null AUTO_INCREMENT comment '编号', `gradename` VARCHAR(50) not null comment '名称',primary key(`gradeid`))ENGINE=INNODB DEFAULT CHARSET=utf8; [Err] 10