Array Flashcards
A _____________ is a way of organizing and
storing data so that it can be accessed and
modified efficiently.
data structure
________ in Java are __________(consisting of
parts all of the same kind.) data structures
implemented in Java as objects.
Arrays
homogeneous
A specific element in an array is accessed by its
_______. Arrays offer a convenient means of grouping
related information.
index
An ________ in an array is a single value stored at a
particular position. Each element shares the same
data type as the array.
element
An __________ is the position of anelement inside an array. In Java, array indices start from 0 (not 1).
index (plural: indices)
A __________ is the physical address in
computer memory (RAM) where an array stores its
elements.
memory location
What are the typesof Java Array
Single Dimensional Array
Double Dimensional Array
Multi Dimensional Array
You can imagine a 1D array as a row, where elements are stored one
after another.
Single Dimensional Arrays
A two-dimensional (2D) array can be visualized as a table or a matrix. It contains rows and columns.
Double Dimensional Arrays
Each element is initialized to a default value, a process known as _________. ____________ is initialization of variables to a default value, as in the initialization of array elements when an array is __________.
auto-initialization
Auto-Initialization
constructed
A ______________ in Java
is a structured way of storing multiple
values of the same data type under a
single variable name.
one-dimensional array (1D array)
The enhanced for loop, also called the _______, is a simplified way to iterate through arrays and collections. It eliminates the need for index tracking, making the code cleaner and easier to read.
for each loop
Accessing an index that is outside the valid range of the array causes a
runtime error.
Array Index Out of Bounds Exception
Arrays have a fixed size—once created, they cannot grow or
shrink.
Fixed Size Limitation
Java provides various utility methods to work with
arrays through the Arrays class in the java.util
package. These methods help with______,
_______, _____, _______, and _________
arrays efficiently.
sorting
searching
copying
comparing
filling
The equals() method checks if
two arrays contain the same
elements in the same order.
Arrays.equals()
The sort() method sorts an array in
ascending order.
Arrays.sort() –
The fill() method sets all elements in an array to a
specific value.
Arrays.fill()
The copyOf() method creates a new array with the
same elements as the original.
Arrays.copyOf()
is used to
search for an element in a sorted array efficiently.
Arrays.binarySearch() method
method is used
to convert a String into a
character array (char[])
toCharArray()
A ________ is an array of arrays.
It stores data in rows and columns
(tabular format).
2D array
Elements are accessed using two
indices: row index and column index.
Also called __________
because they use more than one
dimension (row and column).
multidimensional arrays
Elements are stored row by row in
memory.
Row-Major Order
Elements are stored column by column in
memory
Column-Major Order
_______ are stored in contiguous memory
locations.
Arrays
Arrays are stored in _________________.
contiguous memory
locations
Elements are accessed using ____________.
numeric
indexing
A ____________ 2D array stores elements
of different data types.
heterogeneous
Gives the number of rows in the 2D array.
numbers.length
Iterates over each row before moving to
the next.
Row-Major Order Traversal
Iterates over each column before moving to
the next.
Column-Major Order Traversal
2D array is an array of _____.
arrays
It stores data in ____ and ____ (tabular format).
rows
columns
It stores data in rows and column (_____).
tabular format
Elements are accessed using two indices.______ and ______
Row index and column index
What is columns
Vertical Elements
______ are accessed using two indices
Elements
2D is also called__________ because they use more than one dimensions.
Multidimensional arrays
2D is commonly used in programming to ______ and______ data.
Store
Manipulate
What is rows?
Horizontal elements
Java treats a 2D array as a _______ of 1D arrays.
collection
Each row in a 2D array is _____ to 1D array.
Pointer
Syntax for declaring 2D array:
Two square brackets
Specify the number of rows but leave columns uninitialized.
Double-Dimensional array with only rows initialized.
Creates a _________(rows can have different column sizes).
Jagged array
Arrays are stored in __________.
contagious memory locations.
Elements are accessed 1using _______
numeric indexing
____________ in Java are like the basic units or building
blocks of a Java program.
Methods
A method is a ___________ that performs a
specific task or operation.
group of code
A method is a group of code that performs a
____________.
specific task or operation
a method is a collection of
__________ that work together to complete
a particular job.
statements
Applications of 2D Arrays:
Used in mathematics to represent
__________ and ________.
matrices
complex data structures
____________
Can store:
______
________
Other types of data.
Images.
Text.
Applications of 2D Arrays:
Useful for __________ and
___________.
data analysis
visualization
Java treats a __________ as a collection of
1D arrays.
2D array
Java treats a 2D array as a collection of
___________.
1D arrays
A 2D array in Java has rows and
columns, requiring ______ indices:
One for the _______.
One for the _______.
two
row
column
Syntax for declaring a 2D array
________: Type of values the array can store (e.g., int,
char).
DataType
Syntax for declaring a 2D array
________: Reference variable for the 2D array
object.
ArrayName
Ways to Initialize a 2D Array
______________:
Assign values directly during
declaration.
Static Initialization
Ways to Initialize a 2D Array
____________:
Set the size first, then assign values
later.
Dynamic Initialization
Types of 2D Array Initialization
- Double-Dimensional Array with Only Rows Initialized
Specify the number of rows but leave columns
__________.
uninitialized
- Double-Dimensional Array with Only Rows Initialized
Creates a j_________(rows can have different column sizes).
Useful for _________________ (e.g., storing words of different
lengths).
jagged array
flexible structures
Types of 2D Array Initialization
___________________________:
Not possible in Java.
You must define rows first because a 2D array is an array
of arrays.
Columns are defined per row.
Double-Dimensional Array with Only Columns Initialized
Types of 2D Array Initialization
1.__________________:
Specify the number of rows but leave columns uninitialized.
Creates a jagged array (rows can have different column sizes).
Useful for flexible structures (e.g., storing words of different
lengths).
Initialize each row with a different number of columns
Double-Dimensional Array with Only Rows Initialized
Types of 2D Array Initialization
3.______________________________:
Declare a 2D array without initializing rows or columns.
This is just a _________; no memory is allocated yet.
Must initialize before use.
Double-Dimensional Array with No Rows or Columns
Initialized
reference
A ________ is a 2D array where
each row can have a different number of
columns
jagged array
A jagged array is a 2D array where
each row can have a different number of
___________
columns
Unlike regular 2D arrays, jagged
arrays are not ____________.
Useful when the data structure is
__________ (e.g., varying number of
subjects per student).
rectangular
irregular
Declaring and Initializing a Heterogeneous
2D Array
A heterogeneous 2D array stores ___________
of __________.
elements
different data types
Declaring and Initializing a Heterogeneous
2D Array
A ___________ stores elements
of different data types.
heterogeneous 2D array
Java arrays are _______ by ______all
elements must be of the same type).
homogeneous
default (
To achieve __________, we use a
workaround involving the Object class
heterogeneity
To achieve heterogeneity, we use a
workaround involving the _____
Object class
To achieve heterogeneity, we use a ______ involving the Object
class.
workaround
How to Achieve Heterogeneity in Java
Use the ________:
The Object class is the root of Java’s class ________.
By declaring a 2D array as Object[][], we can store
_______ of any type.
Object class
hierarchy
elements
Declaring and Initializing a Heterogeneous
2D Array
Declare the array as _______
Assign ______ of different types
Object[][]
values
Accessing 2d Array Elements
Since the array is of type Object, you must
_________ elements back to their
original types when _____ them
cast(typecasting)
accessing
Looping Through a 2D Array
Use ________ (a loop inside another loop)
to _______ all elements of a 2D array.
______: Iterates over the rows.
__________: Iterates over the columns of each
row.
nested loops
traverse
Outer loop
nner loop
Row-Major Order Traversal
Iterates over ______ before moving to
the next.
each row
___________
Iterates over each row before moving to
the next.
Row-Major Order Traversal
__________
Iterates over each column before
moving to the next.
Column-Major Order Traversal
Column-Major Order Traversal
Iterates over _____ before
moving to the next.
each column
A data structure is a way of ________ and
______ so that it can be accessed and
modified efficiently.
organizing
storing data
A data structure is a way of organizing and
storing data so that it can be_______ and
________ efficiently.
accessed
modified
Some common data structures include ___,
linked lists, stacks, queues, hash tables, and
trees.
arrays
Arrays in Java are homogeneous(consisting of
parts all of the same kind.) data structures
implemented in Java as ______.
objects
Arrays store one or
more values of a ________ and provide
_______ access to store the same.
specific data type
indexed
Arrays offer a _____ means of grouping
related information.
convenient
