Arrays

• An array is a collection of variables of the same type.
• A variable declared in brackets, [], is an array reference.
• Three steps
  • Declaration - tell the compiler what the name is and the type of its elements.
  • Construction -
  • Initialization

    int numbers[];          // declaration
    numbers = new int[100]; // construction
    for (int i=0; i<100; i++)
    {
      numbers[i] = i;
    }
    

  String username[];
  float[] balance;
  

• Components of an array are accessed by a simple integer index.
• Element indexing begins with the number 0.

  username[0] = "Fred";
  username[1] = "Barney";
  

• The size of an array is easily accessed with the length attribute.

  for (int i=0; i<username.length; i++)
  {
      System.out.println("The user's name is: " + username[i]);
  }
  

• Indexing past the end of an array throws an exception.
• Multidimensional arrays can be created.