Understanding Strings and Characters in Java Programming with String and StringBuffer, Slides of Applications of Computer Sciences

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Chapter 7:

Strings and Characters

Object-Oriented Program

Development Using Java: A

Class-Centered Approach

Objectives

• The String Class
• String Processing
• The StringBuffer Class
• Program Design and Development: Program Performance Measures and Object-Oriented Technology (OOT)
• Common Programming Errors

Creating a String

• Syntax:

String identifier = new String(string-value);

String identifier; identifier = new String(string-value);

String identifier = string-value;

Creating a String (continued)

• Storage for a string is created in memory when a string is created - Location of where the string is stored is placed in a variable
• Called a reference variable

Constructors

• Instantiating an object is the process of using the new operator to create an object
• The name of the constructor method must be the same name as the class
• The String class provides nine different constructors for creating String objects

String Processing

• Strings are manipulated using:
  • Standard String class methods
  • Character-at-a-time methods provided by the Character class

Other String Methods

• The charAt() method permits you to retrieve individual characters in a string
• The last position is always one less than the number of characters in the string

The StringBuffer Class

(continued)

• String class
  • Preferred class for displaying or comparing strings that tend to remain constant
• StringBuffer class
  • Should be used for applications that require:
    • Individual character additions
    • Modifications
    • Multiple text edits