Inheritance

[fread]

Im trying to run this code from a book called "thinking in java"
For some reason the Detergent class is not being called by the program instead it appears to be calling the Cleanser class. Im not sure where is the error b/c everything seems to compile nicely and the cleanser class works fine. Im working on the topic of inheritance.
code->

//: Detergent.java
// Inheritance syntax & properties

class Cleanser{
    private String s = new String("Cleanser\n");
    public void append(String a) { s += a; }
    public void dilute(){ append("dilute()\n"); }
    public void apply(){ append("apply()\n"); }
    public void scrub(){ append("scrub()\n"); }
    public void print() { System.out.println(s); }
    
    public static void main(String[] args){
        Cleanser x = new Cleanser();
        x.dilute();
        x.apply();
        x.scrub();
        x.print();
    }
}
public class Detergent extends Cleanser{
    
    //change a method:
    public void scrub(){
        append(" Detergent.scrub()");
        super.scrub(); //Call base-class version
    }    
    //Add methods to the interface:
    public void foam(){ append(" foam()"); }
    // Test the new class:
    public static void main(String[] args){
    System.out.println("Inside Detergent class");    
        
        Detergent x = new Detergent();
        x.dilute();
        x.apply();
        x.scrub();
        x.foam();
        x.print();
        System.out.println("Testing base class:");
        Cleanser.main(args);
    }
} 

[Turk4n]

To help you little here


OBJECT !

class Cleanser{
    private String s = new String("Cleanser\n");
    public void append(String a) { s += a; }
    public void dilute(){ append("dilute()\n"); }
    public void apply(){ append("apply()\n"); }
    public void scrub(){ append("scrub()\n"); }
    public void print() { System.out.println(s); }
    
    public static void main(String[] args){
        Cleanser x = new Cleanser();
        x.dilute();
        x.apply();
        x.scrub();
        x.print();
    }
}

THE MAIN !

public class Detergent extends Cleanser{
    //change a method:
    public void scrub(){
        append(" Detergent.scrub()");
        super.scrub(); //Call base-class version
    }    
    //Add methods to the interface:
    public void foam(){ append(" foam()"); }
    // Test the new class:
    public static void main(String[] args){
    System.out.println("Inside Detergent class");    
        
        Detergent x = new Detergent();
        x.dilute();
        x.apply();
        x.scrub();
        x.foam();
        x.print();
        System.out.println("Testing base class:");
        Cleanser.main(args);
    }
}

That's it, now should everything work perfectly normal !
Hope you enjoy it

[fread]

Excuse me if im wrong, but its look like u just seperated the code. The Cleanser class and the Detergent class are supposed to be in same file. "Even if you have a lot of classes in a program only the main() for the public class invoked will be called.". By seperating the code i learn nothing. Detergent main() is supposed to call Cleanser main().

[Turk4n]

Excuse me if im wrong, but its look like u just seperated the code. The Cleanser class and the Detergent class are supposed to be in same file. "Even if you have a lot of classes in a program only the main() for the public class invoked will be called.". By seperating the code i learn nothing. Detergent main() is supposed to call Cleanser main().

A main class is not supposed to Inherit from subclasses... Just by using them separating them the output will be.


The Detergent's output

Inside Detergent class
Cleanser
dilute()
apply()
 Detergent.scrub()scrub()
 foam()
Testing base class:
Cleanser
dilute()
apply()
scrub()

The Cleanser's output

Cleanser
dilute()
apply()
scrub()

If you don't understand the mistake you did was this.

The public type Detergent must be defined in its own file

The alternative way to do is making it abstract !
But your variables will not be !

Cannot instantiate the type Detergent

BUT IF YOU REALLY WANT TO DO THE WRONG WAY here it is...

//: Detergent.java
// Inheritance syntax & properties

class Cleanser{
    private String s = new String("Cleanser\n");
    public void append(String a) { s += a; }
    public void dilute(){ append("dilute()\n"); }
    public void apply(){ append("apply()\n"); }
    public void scrub(){ append("scrub()\n"); }
    public void print() { System.out.println(s); }
    
    public static void main(String[] args){
        Cleanser x = new Cleanser();
        x.dilute();
        x.apply();
        x.scrub();
        x.print();
    }
	public void foam() {
	}
}
public abstract class Detergent extends Cleanser{
    
    //change a method:
    public void scrub(){
        append(" Detergent.scrub()");
        super.scrub(); //Call base-class version
    }    
    //Add methods to the interface:
    public void foam(){ append(" foam()"); }
    // Test the new class:
    public static void main(String[] args){
    System.out.println("Inside Detergent class");    
        
        Cleanser x = (Cleanser) new Cleanser();
        x.dilute();
        x.apply();
        x.scrub();
        x.foam();
        x.print();
        System.out.println("Testing base class:");
        Cleanser.main(args);
    }
}

Try to figure why I did this way, you will understand the error you made later or you will post again here complaining...

[fread]

Im not complaining bro just trying to understand and i can take critisism, its all in the learning process. If i offended you, my apologies, i did not want just the solution, as in your first response but an explanation for why what was happening was happening as in your second response. Now i think i grasp the concept. Much thanks!

[Turk4n]

Im not complaining bro just trying to understand and i can take critisism, its all in the learning process. If i offended you, my apologies, i did not want just the solution, as in your first response but an explanation for why what was happening was happening as in your second response. Now i think i grasp the concept. Much thanks!

Well no worries, I am just kinda tired with my fever and school...