Tokens in Java java java Java javascript.pptx

Tokens in Java

1. TOKENS AND TYPES OF TOKENS TOKENS The smallest unit of programming language which is used to compose instructions is known as tokens. TYPES OF TOKENS : Keywords. identifiers. Literals / Data / values.

2. KEYWORDS KEYWORDS : A predefined words which the java compiler can understand is known as keyword. Every keyword in java is associated with a specific task. A programmer can’t change the meaning of a keyword (can’t modify the associated task) . EXAMPLE : We have 50+ keywords in java, class , public , static , void , etc. ,. RULE : Keywords are always written in lower case.

3. IDENTIFIERS IDENTIFIERS : The name given to the component of java by the programmer is known as identifiers. LIST OF COMPONENTS : class method variables interface enum , etc… NOTE : A programmer should follow the rules and convention for an identifier.

4. RULES OF AN IDENTIFIERS : Identifiers should never starts with a number. Identifiers should not have special characters except _ and $. Character space is not allowed in an identifiers. We can’t use keyword as an identifiers.

5. CONVENTIONS CONVENTIONS : The coding or industrial standards to be followed by the programmer is known as convention. NOTE : Compiler doesn’t validate the convention , Therefore if conventions is not followed then we won’t get compile time error. It is highly recommended to follow the convention.

6. CONVENTION FOR CLASS CONVENTION FOR CLASS NAME : Single word - The first character should be in upper case remaining in lower case. Example : Addition , Calculator , Sum , etc… Multi word – The first character of every word should be in upper case remaining in lower case. Example : SquareRoot , PowerOfDigit , FactorialOfDigits , etc…

7. CONVENTION FOR Methods and variables : Single word - Word should be in lower case. Example : a ddition , calculator , sum , etc… Multi word – The first word should be in lower case remaining words should start with uppercase follow with lower case. Example : s quareRoot , powerOfDigit , factorialOfDigits , etc…

8. LITERALS The values or data used in a java program is known as literals. The data is generally categorized into two types Primitive values Non primitive values PRIMITIVE VALUES : Single values data is called as primitive values. NON PRIMITIVE VALUES : The multi valued data is known as non primitive value (group of data).

9. PRIMITIVE VALUE PRIMITIVE VALUES : Single values data is called as primitive values. EXAMPLE : Number character Boolean. NUMBER LITERALS : Integer number literals. Example : 1 , 4 , 67 , 24 , 35 , etc… Floating number literals. Example : 2.3 , 1.0 , 35.5634 , 23.53 , etc…

10. CHARACTER LITERALS : Anything which is enclosed within a single quote ( ‘ ’ ) is considered as a character literal. The length of character literals should be one. EXAMPLE : ‘a’ , ‘G’ . ‘1’ , ‘$’, etc… BOOLEAN LITERALS : Boolean literals are used to write logical values. We have two Boolean literals true false

11. NON PRIMITIVE VALUES NON PRIMITIVE VALUES : The multi valued data is known as non primitive value (group of data). EXAMPLE : String , details of object , etc… STRING LITERALS : Anything enclosed within a double quote ( “ “ ) is known as String literals. The length of the string literals can be anything. They are case sensitive. EXAMPLE : “hello” , “true” , “a” , “123” , “hello@” , “1.1” , etc…

12. SESSION ACTIVITY Write a java program with a class name using a keyword. Write a java program with a class name starting with a number. Write a java program with a class name starting with a special character. Write a java program with a class name starting with “$”. Write a java program with class name as multiple words with space. Write a java program with class name as multiple words without space. Write a java program with class name as multi word and the first letter of each word should be in upper case.