Understanding OOP Concepts: Properties and Methods

Last modified on February 22, 2020 55 sec read

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In part 1, we’ve learned about OPP, Class & Object. Today I’m trying to explain properties and methods. Let’s get started:

Table of Contents

  1. Properties
  2. Methods
  3. Example
  4. Example in Java

Properties

A property is an attribute of an object. We can also say the variables inside a class are called properties.

Methods

A function inside a class is called a method. A method is an action that an object can perform.

Example

Let’s assume a Car class. I’m writing some possible properties and objects of the Car class.

Class: Car
Object: BMW i8, Tesla 3, Audi a3
Properties: Brand, Color, SunRoof
Methods: Horn, Steering

This figure helps us to get a clear idea:

Figure is taken from learnqtp.com

Example in Java

Now let’s try to write the code of Car class:

Car.java
public class Car {
    // properties
    String brand;
    String color;
    Boolean hasSunRoof = true;

    // method
    void horn() {
        System.out.println("Beep...!");
    }

    // method
    void steering() {
        System.out.println("Move the car...!\n");
    }

    // method
    void displayInfo() {
        String sunRoof;

        if (hasSunRoof)
            sunRoof = "has Sunroof";
        else
            sunRoof = "doesn't have Sunroof";

        System.out.println("Car brand is " + brand + ". It's color is " + color + " and " + sunRoof);
    }
}

We’ve written the Car class code. Let’s try to create objects and display information:

AnotherClass.java
public class AnotherClass {
    public static void main(String[] arg) {
        // object bmw
        Car bmw = new Car();
        bmw.brand = "BMW i8";
        bmw.color = "Black";
        bmw.displayInfo();
        bmw.horn();
        bmw.steering();

        // object audi
        Car audi = new Car();
        audi.brand = "Audi a3";
        audi.color = "Red";
        audi.displayInfo();
        audi.horn();
        audi.steering();
    }
}

In the next article, I’ll try to explain constructor & destructor. 🙂

Author

Hey, I'm Md Obydullah. I build open-source projects and write on Laravel, Linux server, modern JavaScript and more on web development.

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