Hi Reiko Mac here in this practical exercise, we will be learning object oriented programming by writing a custom class by defining values, different methods and access them from main method in the main class by using objects and perform various operations by making function calls. So, let's start with this object oriented programming approach we have more flexibility over our program or commands and we have to first declare a public class. This would be a custom class, here we have a lamp class. We have a variable called Boolean or is on for return type Boolean Boolean is stores either true or false value for for a variable. Here we create a method called turn on. Operator anti white because it does not return any value.
Just changed the value of a variable is equal to true. So, when can on method is called it will change the value of his own variable to true. Similarly we may have a turn off method which maintains the value of his own variable to false. It is simple the notion of a switch electrical switch of our world. Now we can say he has how a third method called display is taters. Our visual display the current status of this switch either turn on or off.
I will read displaying a message on the screen. We are very System dot out dot println Tell them to display this message on a screen like on off for like to rally up to anywhere is on real display true or false. Now, let us create the main class from where we have to create a main method that would call the methods in the class lamp. Here we have the main classes example me, you can also create two different files for both different classes. But you have to compile it to classify the first file and second is a main file or you can always write in the same method, same program. Here we create an object for the land class in the Main method lamp is one question in lamb, it will create a new object called l one for lab class allowing us to access its method or relevance to the object to really we may have we can also create multiple objects for the same class.
And we have two different objects l one and l two for the lamb class. Now, we have to call this method for L one object. Let us change the value two on and by calling the method turn on. And then things they start us off as objects are turned off. And then we can display the first instance by or otherwise, display status and lpo. No deflection status.
So, what happens after we do this You can check by hitting dates if you're working already by pressing Ctrl f9 in case you are using an ID simple error showing up they could be fixed well I guess public the name of the file must be their example and we have to make another class not public. So sign up the first my third question stance and change the value to on suggestive saying the light is on true and the secondary status has changed the value to off displaying the display status false. The error was that we could not make the earlier class as a custom class as public. The public class must be the main class there in this ID. However, in your program, you could make both classes as public or you could create a separate file. Similarly, we could access multiple methods by creating multiple instances.
It is useful in cases of real life cases, whenever you will catch the server application. on a website you hit Quantico request, and the program is written only once. However, multiple instances for different users called sessions are being created based on the different objects that are created. On the Run. It could be correlated here with the concept of objects or instances. You can create a wide number of instances And what are each instance has separate set of data or values and perform operations differently based on same concept.
You can have different methods being called from different classes using different objects and show the result here. It will use all kinds of variables made of Boolean, integer, float, character, string, or anything else. You can have also return type here we have used to void return type for each methods. You could have integer float and return the value directly to the screen and no need of having the display status being called will directly display that message.