Arrays and Strings - Object Oriented and GUI Programming - Lecture Slides, Slides of Object Oriented Programming

Download Arrays and Strings - Object Oriented and GUI Programming - Lecture Slides and more Slides Object Oriented Programming in PDF only on Docsity!

1

Chapter 4: Arrays and Strings

2

Basics of Arrays

• Declaration: int myArray []; or int [] myArray;
• Definition: int [] myArray = new int[10];
• Accessing: num = myArray[i]; I should be int
• Array bound check!!!
• Array length: myArray.length
• Initializing:
  • Using assignment statements
  • Using merged declaration and initialization: int myArray = {1, 2, 3};
  • Using a for loop or collection-based for loop:
    • for (declared variable : array name) {………}
  • Using the fill method: Array.fill(arrayname, value); The Array class is found in the util package

4

• String Literals: “This is a string”
• Declare String: String myString;
• Initialize String: String myString = “My String”;
• Arrays of Strings: String [] names = new String[5];
• String concatenation: JoinStrings.java
• String matching: MatchStrings.java & Identity! MatchStrings2.java
• String comparison: SequenceString.java
• String searching: FindCharacters.java
• Extracting Strings: ExtractSubstring.java

Strings

5

• It is a class that looks like the String class but it is not a static one (its objects are mutable)
• Operations such (concat., etc.) are much more efficient using StringBuffer
• Default capacity is 16: StringBuffer buffer = new StringBuffer();
• Methods: length(), capacity(), setLength()
• To concatenate use append() (check java doc.)
• To insert use insert() : buf.insert(5, “ttt”);
• To convert to String object use toString()
• Example: UseStringBuffer.java

StringBuffer Class