The main contents of this chapter include all of the following: First java program, comments, class name/source code filename, main method heading, braces, , compilation and execution, program template, identifiers, variables, assignment statements, initialization statements. | Chapter 3 - Java Basics First Java Program Comments Class Name / Source Code Filename main Method Heading Braces Compilation and Execution Program Template Identifiers Variables Assignment Statements Initialization Statements 1 Chapter 3 - Java Basics Numeric Data Types – int, long Numeric Data Types – float, double Constants Arithmetic Operators Expression Evaluation Increment and Decrement Operators Compound Assignment Operators Type Casting Character Type - char Escape Sequences Primitive Variables vs. Reference Variables String Basics String Methods: equals, equalsIgnoreCase, length, charAt Input - the Scanner Class 2 First Java Program /*************************************** * * John Dean * * This program prints a hello message. ***************************************/ public class Hello { public static void main(String[] args) { ("Hello, world!"); } } // end class Hello 3 Comments Include comments in your programs in order to make them more readable/understandable. Block comment syntax: /* . */ (Note: The /* and */ can optionally span multiple lines) One line comment syntax: // Commented text is ignored by the compiler. Style requirement: Include a prologue section at the top of every program. The prologue section consists of: line of *'s filename programmer's name blank line program description line of *'s blank line 4 Class Name / Source Code Filename All Java programs must be enclosed in a class. Think of a class as the name of the program. The name of the Java program's file must match the name of the Java program's class (except that the filename has a .java extension added to it). Proper style dictates that class names start with an uppercase first letter. Since Java is case-sensitive, that means the filename should also start with an uppercase first letter. Case-sensitive means that the Java compiler does distinguish between lowercase and uppercase letters. 5 main Method Heading . | Chapter 3 - Java Basics First Java Program Comments Class Name / Source Code Filename main Method Heading Braces Compilation and Execution Program Template Identifiers Variables Assignment Statements Initialization Statements 1 Chapter 3 - Java Basics Numeric Data Types – int, long Numeric Data Types – float, double Constants Arithmetic Operators Expression Evaluation Increment and Decrement Operators Compound Assignment Operators Type Casting Character Type - char Escape Sequences Primitive Variables vs. Reference Variables String Basics String Methods: equals, equalsIgnoreCase, length, charAt Input - the Scanner Class 2 First Java Program /*************************************** * * John Dean * * This program prints a hello message. ***************************************/ public class Hello { public static void main(String[] args) { ("Hello, world!"); } } // end class Hello 3 Comments Include comments in your programs in .
