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
  • Hour 6. Using Strings to Communicate
    • Storing Text in Strings
    • Displaying Strings in Programs
    • Using Special Characters in Strings
    • Pasting Strings Together
    • Using Other Variables with Strings
    • Advanced String Handling
    • Workshop: Presenting Credits
    • Summary
    • Q&A
    • Quiz
    • Activities
  • 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

Storing Text in Strings

Strings are a common feature in computer programming because they provide a way to store text and present it to users. The most basic element of a string is a character. A character is a single letter, number, punctuation mark, or other symbol.

In Java programs, a character is one of the types of information that can be stored in a variable. Character variables are created with the char type in a statement such as the following:

char keyPressed; 

This statement creates a variable named keyPressed that can store a character. When you create character variables, you can set them up with an initial value, as in the following:

char quitKey = '@'; 

Note that the value of the character must be surrounded by single quotation marks. If it isn't, the Java compiler will respond with an error when the program is compiled.

A string is a collection of characters. You can set up a variable to hold a string value by using the String text and the name of the variable, as in the following statement:

String fullName = "Ada McGrath Stewart"; 

This statement creates a string variable called fullName and stores the text Ada McGrath Stewart in it, which is the full name of Hunter's pianist. A string is denoted with double quotation marks around the text in a Java statement. These quotation marks will not be included in the string itself.

Unlike the other types of variables you have used—int, float, char, boolean, and so on—the name of the String type is capitalized.

The reason for this is that strings are somewhat different than the other variable types in Java. Strings are a special resource called objects, and the types of all objects are capitalized. You'll be learning about objects during Hour 10, "Creating Your First Object." The important thing to note during this hour is that strings are different than the other variable types, and because of this difference, String is capitalized when strings are used in a statement.

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