section4.md

Section 4: Creating and Using Arrays

4.1 One-dimensional arrays

Declaration

• Array Type
  • int[] String[] MyObject[]
• Array Name
  • intArray stringArray objectArray

int[] intArray;

Instantiation

• can be instantiated with the new operator
• followed by the type of elements
• and array length enclosed in square brackets

intArray = new int[5]; 

Initialization

• initialized with default values when the array is created
• index starts at 0 default is null, 0s, and false...

Arrays can also be instantiatied and initialized using an array initializer

intArray = {1, 2, 3, 4, 5};  
intArray = new int[] {1, 2, 3, 4, 5}; 

4.2 Multi-dimensional arrays

Declaration

• Array Type, with multiple pairs of brackets
  • int[][](2dimensional) String[][][](3dimensional) MyObject[][][](4dimensional)
• Array Name
  • intArray stringArray objectArray

String[][][] stringArray;

Instantiation

• can be instantiated with the new operator
• followed by the type of elements
• and 2 or more pairs of square brackets, each representing a dimention
• *first bracket must contain a length

`intArray = new int[4][6];

Initialization

• can be initialized by assigning values to its elements at all levels(nested for loops)

Multi-dimensional Arrays can also be instantiatied and initialized using an array initializer

int[][] intArray = {{1, 2}, {3, 4, 5}};
int[][] intArray = new int[][] {{1, 2}, {3, 4, 5}};