Inheritance problem

[El Bicho]

Can you take a look at this code?
Although noFoot has no feet he still has 20 fingers. What´s wrong here? Does he have 10 extra fingers coming out of his head?



function Extremities() {
this.hands = 2;
this.feet = 2;
}
Fingers.prototype = new Extremities();
function Fingers() {
this.Fingers = this.hands * 5 + this.feet * 5;
}
twoFeet = new Fingers();
noFoot = new Fingers();
noFoot.feet=0
trace("twoFeet has " + twoFeet.Fingers + " fingers");
trace("noFoot has " + noFoot.feet + " feet");
trace("noFoot has " + noFoot.Fingers + " fingers");

[ScriptFlipper]

is there any difference if you put a semicolon after the line noFoot.feet=0
like this

noFoot.feet = 0;

[El Bicho]

Hi, not really. If you forget a semicolon it can be added with autoformat and you don´t receive any error message. There are plenty of scripts out there running without semicolons.:)

[senocular]

http://www.kirupa.com/developer/oop/AS1OOPInheritance4.htm

[El Bicho]

Hi, thanks, I followed the link but I am still very confused...:upset:

Just what should I add/change/delete to make noFoot have 10 fingers instead of 20?

[Voetsjoeba]

You are setting the feet property to zero after having created the instance. That's why it still has 20 fingers, because the 20 fingers were assigned when it was being created.

You can't first delete it's feet and then create it. So what I'd do is create a method that reassigns fingers. You can then have noFeet execute this method after you've deleted his feet.



function Extremities() {
this.hands = 2;
this.feet = 2;
}
function Fingers() {
this.fingers = this.hands*5+this.feet*5;
}
Fingers.prototype = new Extremities();
Fingers.prototype.updateFingers = function(){
this.fingers = this.hands*5+this.feet*5;
}
twoFeet = new Fingers();
noFoot = new Fingers();
noFoot.feet = 0;
noFoot.updateFingers();
trace("twoFeet has "+twoFeet.fingers+" fingers");
trace("noFoot has "+noFoot.feet+" feet");
trace("noFoot has "+noFoot.fingers+" fingers");
//twoFeet has 20 fingers
//noFoot has 0 feet
//noFoot has 10 fingers