Data Types in Java

Session 1 - Data Types in Java

What is Data ?
 Most of you have shopped online and this is what a typical purchase looks like

1.     You select a product which has a Price, Tax, Quantity
2.     You pay using your Credit Card by entering Name, CC Number, Expiration Date, Billing    Address, Zipcode

Words above in Bold are data.

What is then Data Type ?

   Can we say Price, Tax, Quantity is of type Number because we can apply Arithmetic (+, -, /, *, %) Operations on them, i.e. we multiply Price & Quantity and than add Tax.
Similarly Your Name, Address are text because it doesn't make sense to have Arithmetic Operation on them and in Java we call them String.

Supported Data Types in Java

  String   -  Text

  double  - Real Numbers i.e. 33.2, 20.0 etc

  int         - Non-Real Numbers i.e. 10, 30, 3453 etc

Typical Java Programs using the above Data Types

public class DataTypesDemo {

    public static void main(String[] args) {

        // define a Data Variable message of type String

        String message = "Hello World!";

        

        // print to console i.e. black screen

        System.out.println(message);

    }

}

        Code Snippet - 1

        // define a Data Variables of type int

        int x = 10;

        int y = 20;

        int z = x + y;

        // print to console i.e. black screen

        System.out.println(z);

        Code Snippet - 2

       // define a Data Variables of type int

        double x = 10.0;

        double y = 20.0;

        double z = x + y;

        // print to console i.e. black screen

        System.out.println(z);

  

Question for you.
  what type is Phone No. (i.e. int or String) ?
    Its String since you will never apply Arithmetic Operations on it.

Homework
There are few others Data Types which I missed that can be found in any book.