Inheritance

[paramasivam Ramu]

Read the code below,is it inheritance?.please explain me in realtime example.

college
cse ece mechanical
students,regno students,regno

[Jim Yingst]

Was there supposed to be some code somewhere?

And what's "regno"? I know it's a word in Italian, but not in English as far as I know. I can't tell how it's being used here.

[Raghu Shree]

Hi,
I think you want class structure of the given members. Am I correct? If yes check the below code

class college{
   int collegeId;
   String collegeName;
 
   void setCollegeId(int collegeId){
         this.collegeId=collegeId;
      }
   int getCollegeId(){
   return collegeId;
   }
 
   void setCollegeName(String collegeName)
   {
      this.collegeName=collegeName;
   }
   String getCollegeName()
   {
     return collegeName;
    }
 }
 
 class department extends college{
     int deptId;
     String deptName;
     void setDeptId(int deptId){
          this.deptId=deptId;
 }
 int getDeptId(){
    return deptId;
 }
 
 void setDeptName(String deptName){
       this.deptName=deptName;
 }
 
 String getDeptName(){
      return deptName;
 }
 }
 
class student extends department{
     int regno;
     String studentName;
     void setRegno(int regno){
          this.regno=regno;
 }
 int getRegno(){
    return regno;
 }
 
 void setStudentName(String studentName){
       this.studentName=studentName;
 }
 
 String getStudentName(){
      return studentName;
 }
 }
 
 public class realTime extends student {
    public static void main(String args[]){
       student stud = new student();
       stud.setCollegeId(101);
       stud.setCollegeName("AVC");
       stud.setDeptId(1001);
       stud.setDeptName("CSE");
       stud.setRegno(10001);
       stud.setStudentName("Rajesh");
       System.out.println("-----------Student Details-----------");
       System.out.println(stud.getCollegeId());
   System.out.println(stud.getCollegeName());
   System.out.println(stud.getDeptId());
   System.out.println(stud.getDeptName());
   System.out.println(stud.getRegno());
       System.out.println(stud.getStudentName());
       System.out.println("-------------------------------------");
 }
}

if any doubts reply me..

[paramasivam Ramu]

Raghu Shree,
My question is,is it necessary for an IS-A relationship to compulsarily exists in case of inheritance.
if possible plz explain with a real-time example.
regards,
-ramu

[Boenyamien Manuel]

Hi are you on line

[Boenyamien Manuel]

Hi Paramasivum Ramu.
I see that you are battling with Inheritance.
Here is the solution for the Mobile.java which you ask about.
I gave you a reply on the weekend and had the instantiation the wrong way round.
Here is your solution and I am not using static methods at all.
I gave three instantiations.
You can decide which instantiation to use to produce your desired output.
You can email me if you want further explanation on inheritance.

THE MOBILE.JAVA PROGRAM

class Vertibrate{

public void move(){
System.out.println("Move");

}
}

class Mammal extends Vertibrate{
public void move(){
super.move();
System.out.println("Walks");
}

}

class Dog extends Mammal {
public void move(){
super.move();
System.out.println("Walks on paws");
}

}

public class Mobile {

public static void main(String[] args){

Vertibrate Vertibrates = new Vertibrate();

Vertibrate Mammals = new Mammal();

Vertibrate Dogs = new Dog();


Vertibrates.move();

System.out.println("_____________________");

Mammals.move();
System.out.println("_____________________");

Dogs.move();
System.out.println("_____________________");



}
}

[Joe Sondow]

Originally posted by paramasivam Ramu:
Raghu Shree,
My question is,is it necessary for an IS-A relationship to compulsarily exists in case of inheritance.
if possible plz explain with a real-time example.
regards,
-ramu

It isn't necessary but it is a very, very, very good idea to ensure that there exists an IS-A relationship between child and parent when using inheritance. I would not personally recommend the class structure Raghu Shree suggests, because it cannot logically be said that a department IS-A college, nor that a student IS-A department, nor that realTime IS-A student. A more traditional approach to that set of entities would say that a college HAS-A department, and that a department HAS-A student.

I'm not entirely clear on the example in the original posting, but it does not suggest inheritance to me. A simple example of inheritance might be something like this:

Vehicle
|
Car
|
BMW

public class Vehicle {}
public class Car extends Vehicle {}
public class BMW extends Car {}