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How do I write variable names in Java?
While choosing an identifier to declare a variable in Java you need to keep the following points in mind.
- The name of the variable should begin with either alphabet or, an underscore (_) or, a dollar ($) sign.
- The identifiers used for variables must not be keywords.
- No spaces or special characters are allowed in the variable names of Java.
- Variable names may contain 0 to 9 numbers (if not at the beginning).
- Variable names are case sensitive i.e. MY_NUM is different from my_num.
- If you use two words in a identifier then the you should follow camel case first letter of first word should be in lowercase and the first letters of later words should be in lower case ex: myNum.
Example
Following example shows various possible identifiers used to declare a variable in Java.
public class VariableTest { public static void main(String args[]) { // Declaring a variable named num int num = 1; int _num = 10; int $num = 100; int num123 = 1000; int NUM = 10000; int myNum = 100000; // Printing the value of the variable num System.out.println("value if the variable num: "+num); System.out.println("value if the variable _num: "+_num); System.out.println("value if the variable $num: "+$num); System.out.println("value if the variable num123: "+num123); System.out.println("value if the variable NUM: "+NUM); System.out.println("value if the variable myNum: "+ myNum); } }
Output
value if the variable num: 1 value if the variable _num: 10 value if the variable $num: 100 value if the variable num123: 1000 value if the variable NUM: 10000 value if the variable myNum: 100000
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