package?集合.Collection;

import?java.util.ArrayList;
import?java.util.List;

//測試泛型
public?class?TestGeneric?{
????/**
?????*?帶有泛型---Course,的List類型屬性
?????*?*/
????public?List<Course>?courses;


????public?TestGeneric(){
????????this.courses?=?new?ArrayList<Course>();
????}
????/**
?????*?測試添加
?????*?*/

????public??void??testAdd(){
????????Course?cr1?=?new?Course("1","大學語文");
????????courses.add(cr1);
????????//泛型集合中，不能添加泛型規定的類型以外的對象，否則會報錯！
????????//courses.add("能否添加一些奇怪的東西？");
????????Course?cr2?=?new?Course("2","java基礎");
????????courses.add(cr2);
????}

????/**
?????*?測試循環遍歷
?????*?*/
????public?void?testForEach(){
????????for?(Course?cr:){??為什么(Course?cr:Courses)?Courses?會報錯
????????????System.out.println(cr.id+":"+cr.name);
????????}
????}


????public?static?void?main(String[]?args)?{
????????TestGeneric?tg?=?new?TestGeneric();
????????tg.testAdd();
????????tg.testForEach();

????}

}
Error:(34,?24)?java:?找不到符號??符號:???變量?Courses??位置:?類?集合.Collection.TestGeneric