Chapter 2.4, Problem 2.4.1CP

Program Plan Intro

Identifiers:

Identifier is the name of the element which is used to identify class, method, and variable in a program.

Example declaration of variable identifier:

data_type identifier-name;

Here,

• “data_type” is to mention the type of the identifier.
• “identifier-name” is the name of the identifier.

Rules of defining identifiers:

To declare an identifier, the programmer should follow the below rules:

• An identifier can use sequence of characters like digit, letters, underscores (_), and dollar signs ($).
• The identifier must not be a predefined word.
• The identifier cannot be “true”, “false”, or “null”.
• An identifier cannot start with digit. It can start with letter, underscore (_), or dollar sign ($).
• It can any of length and cannot use special characters.

Keywords:

Keyword is the reserved word by a program. Because, it has special meaning such as abstract, new, private, etc.