- TuanLQ7
- Easy
- 100 Points
Task
Create the Student
class with the following information:
Explanation:
name, address, gpa
attributes describe the name, address and GPA of aStudent
.Student(name: String, address: String, gpa: double)
is a. constructor with parameter which is used to initializing attributes.toString()
is the method which overridesObject
class. It returns the object information in theString
format. For example, ifname = "Kien", address = "Ha Noi", gpa = "6.6"
, thetoString()
method will return the following result:"Name: Kien, address: Ha Noi, GPA: 6.6"
.
A program to test Student
class:
public class Entry {
public static void main(String[] args) {
Student s = new Student("Kien", "Ha Noi", 6.6);
System.out.println(s);
}
}
When the above code is compiled and executed, it produces the following result:
Name: Kien, addres: Ha Noi, GPA: 6.6
Theory
This article will give you better understanding about Object
class. First of all, see the following example:
class Student{
}
public class Entry {
public static void main(String[] args) {
Student s = new Student();
System.out.println(s.hashCode());
System.out.println(s.toString());
System.out.println(s.getClass());
}
}
When the above code is compiled and executed, it produces the following result:
1554547125
[email protected]
class OOP.Student
Looking at the above example, you will wonder why the Student class has methods like hashCode(), toString(), getClass()
when you do not declare these methods. The reason is that all classes in Java are inherited from Object
class and Object
class have these methods
In addition to the above methods, the Object
class also has a number of other methods, in which toString()
is the method used to represent the object as a string. In fact, the toString()
is very useful. For example, when you call the System.out.println()
function with an object, the program will display the toString()
method of that object:
public class Student {
private String name;
private String address;
private double gpa;
public Student(String name, String address, double gpa) {
this.name = name;
this.address = address;
this.gpa = gpa;
}
@Override
public String toString() {
return "Name: " + name + ", address: " + address + ", GPA: " + gpa;
}
}
When the above code is compiled and executed, it produces the following result:
Name: Kien, age: 23
As you can see, it is possible to use the toString()
method instead of the display()
method you learned in previous articles.
Instruction
You need to create the Student
class like this:
public class Student {
private String name;
private String address;
private double gpa;
public Student(String name, String address, double gpa) {
this.name = name;
this.address = address;
this.gpa = gpa;
}
@Override
public String toString() {
return "Name: " + name + ", address: " + address + ", GPA: " + gpa;
}
}
- Lớp Student có phương thức name với phạm vi truy cập private
- Lớp Student có phương thức address với phạm vi truy cập private
- Lớp Student có phương thức gpa với phạm vi truy cập private
- Phương thức khởi tạo có tham số Student(name: String, address: String, gpa: double) và phương thức toString được cài đặt đúng theo yêu cầu đề bài.