重写错误Java,程序不读取两个方法,只读取一个
我有这个密码重写错误Java,程序不读取两个方法,只读取一个,java,class,object,overriding,Java,Class,Object,Overriding,我有这个密码 public class Student extends Person { //id represents the student's ID private int id; //grade represents the student's grade in the course private Grade grade; //constructor allows user to define first and last names, id,
public class Student extends Person {
//id represents the student's ID
private int id;
//grade represents the student's grade in the course
private Grade grade;
//constructor allows user to define first and last names, id, and grade of student in demo
public Student(String fName, String lName, int id, Grade grade) {
super(fName, lName);
this.id=id;
this.grade=grade;
}
//get methods for fields
public int getId() {
return id;
}
public Grade getGrade() {
return grade;
}
//toString prints out the string from person class along with id and grade fields in formatted string
public String toString() {
return super.toString()+"'s id is " + id + "." +getGrade();
}
}
还有这个密码。问题在于,toString方法使用passFailGrade getGrade()返回值,而不是类中的方法
public class Grade {
private double score;
public Grade(double score) {
this.score=score;
}
public void setScore(double score) {
this.score=score;
}
public double getScore() {
return score;
}
public char getGrade() {
if (getScore()>=90)
return 'A';
else if (getScore()>=80)
return 'B';
else if (getScore()>=70)
return 'C';
else if (getScore()>=60)
return 'D';
else
return 'F';
}
public String toString() {
return "\nThe student recieved a " + getGrade() +
" and had a mark of " + getScore() + ".";
}
}
不确定PassFailGrade
中是否有问题:
public class PassFailGrade extends Grade {
public PassFailGrade(double score) {
super(score);
}
public char getGrade() {
if (getScore()>=50)
return 'Y';
else
return 'N';
}
public String toString() {
return "(Y for yes/N for no) The student passed their course ("
+ getGrade()+ ")." + super.toString();
}
}
然后演示类只需在构造函数中定义并打印
public class StudentDemo {
public static void main(String[] args) {
PassFailGrade bo= new PassFailGrade(98);
Student s1 = new Student("bob", "blake", 123, bo);
System.out.println(s1);
}
}
输出:
bob blake's id is 123.(Y for yes/N for no) The student passed their course (Y). The student recieved a Y and had a mark of 98.0.
鲍勃·布莱克的id是123。(Y代表是/N代表否)该学生通过了他们的课程(Y)。这个学生得了一个Y,得了98.0分。
实际上,您正在重写
getGrade()
方法。这是您打算做的事情,但现在在调用super.toString()
时遇到了问题—它仍然使用您重写的方法
您可以通过以下方式将PassFailGrade
中的更改为字符串来解决此问题:
@Override
public String toString() {
return "(Y for yes/N for no) The student passed their course ("
+ getGrade()+ ")." + "\nThe student recieved a " + super.getGrade() +
" and had a mark of " + getScore() + ".";
}
请注意,我只调用super.getGrade()
。这将产生正确的结果。你能说出哪个是PassFailGrade
类,哪个是Student
类吗?Student类是一个更广泛的类,它定义了名称,并且在ToString中有一个getGrade()。你展示了两个getGrade
方法?哪些属于哪个类别?passfailgrade类别和grade类别passfailgrade是grade的一个扩展。你能在上面共享的代码中添加类签名吗?这样我们就可以更好地理解你的代码了?谢谢,我的代码中确实出现了错误,这是错误的,很抱歉误导了任何人。事实上,我没有看到你的代码有问题。这是我们任何人都可能犯的简单错误。