Java Inheritance Questions | Best Practise

Question

Question: Is this good or bad practise? Any tips on improving this code?
I've realized that I learn coding best by using math examples, so I have created this method to first calculate a square and then the area of a pyramid , by inherit square-file
So, first there's the square-file named: square.java
```java
public class square {
public double calculateSquare(double height, double width){

double area = height * width;
  return area;
}
}
```
... and there's the pyramid-file named: pyramid.java (which extends from the square-file)
```java
public class pyramid extends square {
  public double pyramidArea (){
   return 0.5;
  }
  public static void main (String[] args){
    square squareObject   = new square();
    pyramid pyramidObject = new pyramid();
    double aSquare        = squareObject.calculateSquare(2, 7);
    double aPyramid       = pyramidObject.pyramidArea() * aSquare;
    System.out.println(aPyramid);
  }    
}
```
So, feel free to express tips and opinions if there's something I should change or improve! Thanks! Sry for my english, my native langauge is swedish
[MOD: edited code blocks - srh]

Ryan Ruscett · Answer

Hola,
This is a tuff question to be honest. If it works, I say go with it. There are several ways in which you could utilize this. If you are calling a method throughout your program. It would make sense to make it static. This way you don't have to instantiate the object square, which just takes up space. Although, in this day and age space is almost trivial. 
The idea behind inheritance is two fold. It's to enhance an object, and it's to enforce rules on an object. 
For example. If I have a general car class, I know all cars have 4 wheels. So I could have a base class that sets wheels to 4. Not all cars have 4 doors tho. I could create an abstract method (without a body) that requires me to enter in the number of doors. Now, say I am writing a sports car class, and I know sports cars have 2 doors. If I inherit from the general class car, it already gives me 4 wheels so I don't need to bother with that. But it forces me to use the method or override the method for defining car doors. Now I can define 2 doors instead of 4. Same goes for if I have a family car class where a family car would have 4 doors instead of 2. I am building upon an object as I go along by inheriting it's default information. 
So is inheritance the best option for this? Probably not the best, but like I said before. If it works, go for it. You could make it static as mentioned above, but I also don't see a need to make it part of it's own class. It could exist, just not evident in a simple example like you have here. You could use annotations to do the computation of any value or static inner classes to define the computation within the same class.  All of which would be a valid option. 
it all really depends on the scope of the program/project. How many people are working on it, how big it's going to be, how complicated etc.
Does this help at all? It's a lot I know. But designing how to code software is so depending on so many other things. It's hard to say one way is the best way ya know.

Welcome to the Treehouse Community

Looking to learn something new?

Björn Norén

Björn Norén

Java Inheritance Questions | Best Practise

1 Answer

Ryan Ruscett

Ryan Ruscett

Björn Norén

Björn Norén