list中加不进去

Question

  for(i=0;i<count;i++){     System.out.print("请输入姓名："); sj.setName(sc.next()); System.out.print("请输入年龄："); sj.setAge(sc.nextInt()); System.out.print("请输入成绩："); sj.setGrade(sc.nextDouble());         list.add(sj);      }      for (int j = 0; j < list.size(); j++) {        System.out.println(list.get(j));      }  

Answer 1

list<sj> list=new arrayList<sj>();

Answer 2

要先有对象才能add进去

Answer 3

for循环中得先定义对象实例 ，你没有定义  Student s= new Student();