Question

尝试做菜单选择，但不知道为什么它会工作。当我完成添加一所学校时，我想回去菜单。我如何退出并打印ARRAYLIST的所有信息？

打印菜单
用户选择创建小学，大学或高中生
提示用户提供适当的信息
创建适当的对象（调用构造函数）
将对象放入ArrayList学生
打印出所有学生
重复直到用户从菜单中选择“退出”

  System.out.println("Please select type of object to create:");
    System.out.println(
 "1) Elementry School\n2) High School\n3) College Student\n4)Print out all students\n5)Exit");
   int menuItem = Integer.parseInt(in.nextLine());
    while (menuItem != 5) {
        if (menuItem == 1) {
            System.out.println(
                    "You have selected to create a profile of a Elementary School Kid ..... ");
            System.out.println("Please enter the full name: ");
            String name = in.nextLine();
            System.out.println("Please enter the Age: ");
            int age = Integer.parseInt(in.nextLine());
            System.out.println(
                    "Please enter the name of the Elementry School: ");
            String eschool = in.nextLine();
            System.out.println("Please enter the City: ");
            String city = in.nextLine();
            System.out.println("Please enter the name of the Teacher: ");
            String tname = in.nextLine();
            System.out.println("Please enter the Room No.: ");
            int rno = Integer.parseInt(in.nextLine());
            students.add(new ElementarySchoolStudent(name, age, city, eschool,
                    tname, rno));
        }

        else if(menuItem==2){
            System.out.println(
                    "You have selected to create a profile of a High School student ..... ");
            System.out.println("Please enter the full name: ");
            String n = in.nextLine();
            System.out.println("Please enter the Age: ");
            int a = Integer.parseInt(in.nextLine());
            System.out.println(
                    "Please enter the name of the High school: ");
            String highsch = in.nextLine();
            System.out.println("Please enter the City: ");
            String add = in.nextLine();
            System.out.println("Please enter the counselor's name:");
            String counselor=in.nextLine();
            System.out.println("Please enter student’s gpa:");
            double g=in.nextDouble();
            System.out.println("Please enter the year of graduation:");
            int year=in.nextInt();
            students.add(new HighSchoolStudent(n,a,add,highsch,counselor,
                      year, g));
        }

        else if(menuItem==3){
            System.out.println(
                    "You have selected to create a profile of a college student ..... ");
            System.out.println("Please enter the full name: ");
            String n = in.nextLine();
            System.out.println("Please enter the Age: ");
            int a = Integer.parseInt(in.nextLine());
            System.out.println(
                    "Please enter the name of the College: ");
            String college = in.nextLine();
            System.out.println("Please enter the City: ");
            String add = in.nextLine();
            System.out.println("Please enter the major of the student:");
            String mjr=in.nextLine();
            System.out.println("Please enter student's gpa:");
            double g=in.nextDouble();
            students.add(new CollegeStudent(n,a,add,college,mjr,g));
        }

        else if(menuItem==4){
            for(Student current : students)
            System.out.println(current.printStudent());
        }


    }

}

Answer 1

将您的菜单放入while循环中，以便每次输入如下选项时都会打印：

int menuItem = 0;
while (menuItem != 5) {
    System.out.println("Please select type of object to create:");
    System.out.println("1) Elementry School\n2) High School\n3) College Student\n4)Print out all students\n5)Exit");
    menuItem = Integer.parseInt(in.nextLine());
    if (menuItem == 1) {
        ...
    }
    ...
}

if循环中的if语句JAVA

1 个答案: