Question

我想知道是否有人能告诉我为什么我会在第175行收到错误

Student george= new Student("George Flintstone", 21, "Politics", 3.1);

据说没有类型的人可以访问的封闭实例。我已经查看了其他类似的问题，但我对java不太熟悉，所以我找不到答案，至少有一个我理解得很好。这是我的简介到java类的作业。我在常见问题解答中没有看到任何关于我不能在家庭作业上寻求帮助的内容，但是我承认我没有仔细阅读，所以如果我违反某些规则或者其他规则就让我知道。

另外，很抱歉发布了这么多代码，我不确定它的哪些部分可能很重要。

Public class Person {

    String name;
    int age;

    public Person(String n, int a)
    {
        name = n;
        age = a;
    }

    public Person()
    {
        name = "Bob";
        age = 24; 
    }

    public void set_Person(String n)
    {
        name = n;
    }

    public void set_Person(int a)
    {
        age = a;
    }

    public void set_Person(String n, int a)
    {
        name = n;
        age = a;
    }

    public String get_Name()
    {
        return name;
    }

    public int get_Age()
    {
        return age;
    }

    public boolean equals(Object ob)
    {
        Person p = (Person)ob;
        if(ob == null)
            return false;
        if(name.equals(p.name) && age == p.age)
            return true;
        else
            return false;
    }

    public String toString()
    {
        String temp = name + " is " + age + " years old ";
        return temp;
    }

class Student {

    String major;
    double gpa;
    Person p = new Person();

    Student(String n, int a, String m, double g )
    {
        p.set_Person(n,a);
        major = m;
        gpa = g;
    }

    Student()
    {
        p.set_Person("Ben", 10);
        major = "compsci";
        gpa = 3.5;
    }

    public void set_Student(String n, int a, String m, double g)
    {
        p.set_Person(n,a);
        major = m;
        gpa = g;
    }

    public void set_Student(String n)
    {
        p.set_Person(n);
    }

    public void set_Student(int a)
    {
        p.set_Person(a);
    }

    public String getStudentName()
    {
        String temp = p.get_Name();
        return temp;
    }

    public int getStudentAge()
    {
        return p.get_Age();
    }


}

class Family {


    Person [] per_array;
    int person_count = 0;
    Person temp = new Person();

    Family(int members)
    {
        Person[] per_array = new Person[members];
    }

    public void addPerson(Person p)
    {
        boolean check = false;

        for(int count = 0; count < per_array.length; count++){
            if(per_array[count].equals(p))
            {
                System.out.println("That person is already a member of this family");
                check = true;
            }
        }
        if(check = false){
            per_array[person_count] = p;
            person_count++;
        }
    }

    public void addPerson(Student s)
    {
        temp.set_Person(s.getStudentName(), s.getStudentAge());
        boolean check = false;

        for(int count = 0; count < per_array.length; count++){
            if(per_array[count].equals(temp))
            {
                System.out.println("That person is already a member of this family");
                check = true;
            }
        }

        if(check = false){
            per_array[person_count] = temp;
            person_count++;
        }

    }

    public void printOutFamily()
    {
        for(int count = 0; count < per_array.length; count++)
        {
            per_array[count].toString();
        }
    }
}

    public static void main(String[] args) {
        Person fred= new Person("Fred Flintstone", 50);
        System.out.println("created " + fred);

        Person wilma = new Person("Wilma Flintstone", 48);
        Student george= new Student("George Flintstone", 21, "Politics", 3.1);
        System.out.println("created " + george);

        Student sue= new Student("Sue Flintstone", 24, "Nursing", 3.3);
        Student anotherGeorge= new Student("George Flintstone", 21, "Math", 3.4);
        Person yetAnotherGeorge= new Person("George Flintstone", 21);

        Family f = new Family(10);
        f.addPerson(fred);
        f.addPerson(wilma);
        f.addPerson(george);
        f.addPerson(sue);
        f.addPerson(anotherGeorge);
        f.addPerson(yetAnotherGeorge);

        anotherGeorge.set_Student("Georgie Flintstone");
        f.addPerson(anotherGeorge);

        f.printOutFamily();
    }

}

Answer 1

Student是一个内部类，它与Person的特定实例相关联，这意味着调用它是无效的

new Student("George Flintstone", 21, "Math", 3.4);*

使内部类static允许它工作。静态内部类（也称为嵌套类）不需要外部类的实例Person。

不能访问类型为Person的封闭实例

1 个答案: