Create a Variable in Java
Revision as of 02:15, 26 April 2022 by Kipkis (Kipkis | contribs) (Text replacement - "[[Category:J" to "[[Category: J")
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
- Create a simple Java program. An example is provided called Hello.java : Template:CodeBox
- 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
- Integer data types : Used to store integer values like 3, 4, -34 etc
- 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';
- Understand how this works. It is basically "type name = value".
- 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
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.
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