AP CS - Chapter 18

arrays

data structure with a group of elements of the same type with an index; memory to hold the whole array in the same spot is allocated.

1-dimensional array

an array with a single line or column of data

what types of variables are array variables?

reference variables - arrays are objects that need to be initialized to use

how to create a new array?

int an_array = new int[6]; //int = data type of the array; stored with default values

int[ ] myIntArray = {1,324,5,6,67}; //initializer list - specific values

default values

numeric - 0 or 0.0; boolean - false; object reference - null

what value do array indexes start at?

0

how to get or set the element value?

System.out.println(array_name[4])

how to get the length of an array?

array_name.length // cannot be used for a null array

are arrays mutable or immutable?

immutable - elements can’t be added or removed without creating a new array

traversing, iterating, walking through an array

sequentially accessing each array element

last valid index of an array

array length - 1

where is the index variable declared when using a while loop?

outside the loop