Week 11 Part 2 Flashcards
o T/F – each element in an Array is the same data type.
True
o T/F – Each element in an array is differentiated by a subscript
True
o T/F – Each array element can be used in the same way as a single item of the same data type
True
o Arrays can be used to replace __ structures with several different user inputs
if
o It’s good practice to use _________ for array sizes
constants
o Why are constants good for array sizes?
Easier to change the array size later, removes magic numbers
o The most basic method of searching an array is
A linear search in a loop where the loop control variable also acts as the arrays index
- What is a Parallel Array?
An array that runs concurrent to another. One array for different pieces of data.
- Why should we not use Parallel Array in Java?
High maintenance, you need to keep the array indexes synchronized
o Solution to Parallel Array problem
Create a record object that an array can reference instead
customer Cust = new Customer(id, name, house);
Index[index] = customerId(index+1, name, house)
index [2] = customerId(index+1, name, house)
o A ___ loop is a natural way to sequentially access each element in an array. What is this process known as?
For, iterating over the array
What is an array in Java?
An object or reference type. It’s of reference regardless of whether the stored values are primitive.
Java can have elements of __________ type or _________
primitive, reference
o In java indexes are ____ or anything that can be promoted to an ___
Ints, int
o The lowest index value for an array is _
0
o T/F – In java, an array can be resized after it is instantiated
False
T/F - every array has a final instance field “length”
True
o What is the command for the size of the array? Will this let you change the array size?
arrayName.length. No
o Once instantiated, are arrays aware of their size in Java?
Yes
o A: DataType arrayName[]; B: DataType[] arrayName; Which syntax is preferred?
B
o Array reference variables are automatically set to ____ after they are declared
Null (might be better to set this explicitly to help other programmers)
o If we declare an array - num int[] numbers; - Does this place an array object in memory?
No, this is only a declaration
o Are either of these local scope array reference variables initialized? Is this behaviour consistent with other local scope reference variables?
Public void doStuff(){
String[] someNumbers;
String[] otherNumbers = null; }
String[] someNumbers is not initialized, String[] otherNumbers = null is initialized.
This is the same as other local scope reference variables. NOTE – they are still just declarations, not array objects
o T/F – You are permitted to specify the size of the array in the same box when declaring it in Java
False
o T/F – You are permitted declare and initialize an Array on the same line
True
