override in processing 1.51

Programming Questions

h9230669

in Programming Questions • 5 months ago

Hello, I'm trying to use some override Technic in processing

However I found it's a little wired,

here's a small example....

class father{
String a = "i am father";
father(){}
public void printa() {println(this.a);}
}
class child extends father{
String a = "i am child";
child(){}
}
void setup(){
father f = new father();
child c = new child();
f.printa();
c.printa();
}

this will printout these two lines...

i am father
i am father

But I already declare the child's value as "i am child"

why I still get the parent's value with method printa() ?

is this not possible to make > child class use child value by using father method ?

please help, thanx ... <(_ _)>

ps. my friend said maybe i should using "override" in child class just like in java

override string a= "i am child";

but seems it cannot using override in processing

ps. I'm using processing 1.51

Replies(3)

cageehv

Re: override in processing 1.51

5 months ago

Why not doing it this way?

Rolf van Gelder

class father {
String a = "i am father";
father() {
}
public void printa() {
println(this.a);
}
}
class child extends father {
String a = "i am child";
child() {
}
public void printa() {
println(this.a);
}
}

void setup() {
father f = new father();
child c = new child();
f.printa();
c.printa();
}

h9230669

Re: override in processing 1.51

5 months ago

many thanks for your rapidly replying :)

I've tried this before and it's really works

However, I thought it's not a OOP concept

Above is just a simple task

actually I've got many methods to inherent from parent class

I don't want to duplicate all these same method from parent to child class

I thought the polymorphism & overide feature

are the basement and the most powerful character in OOP concept

and I wish to apply in processing.

Is there any other way don't need to repeat the same lines in the child class?

GoToLoop

Re: override in processing 1.51

5 months ago

Here's a slightly different take at your sample:

class Father {
  String myStr = "I am a father!";

  void printVar() {
    println(myStr);
  }
}

class Child extends Father {
  String myStr = "I am a child!";
}

void setup() {
  Father f = new Father();
  Child  c = new Child();

  f.printVar();
  c.printVar();

  println(f.myStr);
  println(c.myStr);

  exit();
}

Seems like an inherented method uses its parent's original fields!

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