Create a Variable in Java

Variables are one of the most important concepts in computer programming. They store information such as letters, numbers, words, sentences, true/false, and more. This will give you an introduction into using variables in Java. It is not intended as a complete guide, but as a stepping stone into the world of the computer programmer.

Steps

  1. Create a simple Java program. An example is provided called Hello.java :
  2. Scroll to a place where you want to insert the variable. Remember: If you place a variable in the main class, you can reference it anywhere. Choose the type of variable you need.
    • Integer data types : Used to store integer values like 3, 4, -34 etc
      • byte
      • short
      • int
      • long
    • Floating Point data type : Used to store numbers having fractional part like 3.479
      • float
      • double
    • Character data type: Used to store characters like 's', 'r', 'g', 'f' etc
      • char
    • Boolean data types : Can store either of the two values: true and false
      • boolean
    • Reference data types : Used to store references to objects
      • Array types
      • Object types like String
  3. Create the variable. Here are examples of how to create and assign a value to each type.
    • int someNumber = 0;
    • double someDouble = 635.29;
    • float someDecimal = 4.43f;
    • boolean trueFalse = true;
    • String someSentence = "My dog ate a toy";
    • char someChar = 'f';
  4. Understand how this works. It is basically "type name = value".
  5. Protect variables from being edited later, optionally, by adding "final type name" between the parentheses in the second line of your code (public static void main).
    • final int someNumber = 35; Adding the 'final' here means that the variable 'someNumber' cannot be changed later
    </ol>

    Tips

    • Each variable in a program must have a unique name or you'll bump into errors.
    • In Java, all lines of instructions must end in ;
    • Different variables can have the same name in certain circumstances. For example: A variable inside a method can have the same name as that of an instance variable.

    Things You'll Need

    • JDK. This task is so simple that any version is suitable.
    • A text editor that can save the text in 'plain text' format.
    • An IDE like NetBeans to make things easier.

    Related Articles

Retrieved from "https://kipkis.com/index.php?title=Create_a_Variable_in_Java&oldid=268971"