CodeHS Unit 4

Encapsulation

Keeping data safe inside an object and controlling who can access or change it

How do you initialize an array called arr of 5 ints with default values?

int [] arr = new int [5];

Which index is the last element in an array called highTemps?

highTemps.length - 1;

When would you use an enhanced for loop instead of a traditional for loop?

If you want to access every element of an array and want to refer to elements through a variable name instead of an array index.

Primitives

Int, double, boolean, char

Can primitive values be replaced in enhanced for loops?

Cannot be replaced because an enhanced for loop makes a copy of the primitive value, so the copy is being replaced

Can ArrayLists use primitives?

No, they use objects

Wrapper classes

Integer, Double, Boolean, Character

Autoboxing

Java automatically converts primitive into object

Unboxing

Java automatically converts object into primitive

parseInt()

Converts a String into an int primitive

Declare an array

int[] nums;