Sams Teach Yourself Java 2 in 24 Hours

By Rogers Cadenhead

• Table of Contents
  • Copyright
  • About the Author
  • About the Technical Editor
  • Acknowledgments
  • We Want to Hear from You!
  • Reader Services
  • Introduction
  • Hour 1. Becoming a Programmer
  • Hour 2. Writing Your First Program
  • Hour 3. Vacationing in Java
  • Hour 4. Understanding How Java Programs Work
  • Part II: Learning the Basics of Programming
  • Hour 5. Storing and Changing Information in a Program
    • Statements and Expressions
    • Assigning Variable Types
    • Naming Your Variables
    • Storing Information in Variables
    • Workshop: Using Expressions
    • All About Operators
    • Summary
    • Q&A
    • Quiz
    • Activities
  • Hour 6. Using Strings to Communicate
  • Hour 7. Using Conditional Tests to Make Decisions
  • Hour 8. Repeating an Action with Loops
  • Part III: Working with Information in New Ways
  • Hour 9. Storing Information with Arrays
  • Hour 10. Creating Your First Object
  • Hour 11. Describing What Your Object Is Like
  • Hour 12. Making the Most of Existing Objects
  • Part IV: Programming a Graphical User Interface
  • Hour 13. Building a Simple User Interface
  • Hour 14. Laying Out a User Interface
  • Hour 15. Responding to User Input
  • Hour 16. Building a Complex User Interface
  • Part V: Creating Multimedia Programs
  • Hour 17. Creating Interactive Web Programs
  • Hour 18. Handling Errors in a Program
  • Hour 19. Creating a Threaded Program
  • Hour 20. Reading and Writing Files
  • Part VI: Creating Multimedia Programs
  • Hour 21. Using Fonts and Color
  • Hour 22. Playing Sound Files
  • Hour 23. Working with Graphics
  • Hour 24. Creating Animation
  • Part VII: Appendixes
  • Appendix A. Tackling New Features of Java 2 Version 1.4
  • Appendix B. Using the Java 2 Software Development Kit
  • Appendix C. Programming with the Java 2 Software Development Kit
  • Appendix D. Using Sun ONE Studio
  • Appendix E. Where to Go from Here: Java Resources
  • Appendix F. This Book's Web Site

Statements and Expressions

Computer programs are a set of instructions that tell the computer what to do. Each of these instructions is called a statement. The following example from a Java program is a statement:

int HighScore = 400000; 

You can use brackets to group a set of statements together in a Java program. These groupings are called block statements. Consider the following portion of a program:

1: public static void main(String[] arguments) { 
2:    int a = 3; 
3:    int b = 4; 
4:    int c = 8 * 5; 
5: } 

Lines 2–4 of this example are a block statement. The opening bracket on Line 1 denotes the beginning of the block, and the closing bracket on Line 5 denotes the end of the block.

Some statements are called expressions because they involve a mathematical expression. Line 4 in the preceding example is an expression because it sets the value of the c variable equal to 8 multiplied by 5. You'll be working with several different types of expressions throughout the coming sections.

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