This document provides an introduction to arrays in Java programming. It defines what arrays are, how they can store multiple values of the same type, and how they use indexes to access elements. The objectives are to develop programs that create and manipulate arrays. Key concepts covered include declaring and initializing arrays, assigning values, accessing elements, and using arrays in examples like storing image pixels or game grids. Code snippets demonstrate creating arrays of different types, assigning values, and a for loop to print array elements.

1. Introduction to Computer Programming
Lab 2
Arrays
Neveen Reda

2. Arrays in action
0 There are many uses for arrays
0 For example image pixels are represented using
arrays
Neuroph (2012)

3. Arrays in action
0 Arrays can also be used
in creating grids for
games.
Eckert (2009)

4. Lesson Objectives
After this lesson you will be able to:
3.Develop Java programs that create arrays and perform
different operations on them.
5.Determine the functionality and output of any given
program that performs array manipulations.

5. Arrays
0 Why arrays?
 Individual variables can only hold one value at a time, Arrays
can holds multiple values (Abdennadher , 2010).
0 “An array is a data structure that defines an indexed
collection of a fixed number of data elements.” (Mughal &
Rasmussen, 2009).

6. Arrays
0 The position of an element in an array is called the index.
0 If array X contains 10 elements, the first element will be at
position (index) '0' and the last element is at position '9'
Oracle (2012)

7. Arrays Declarations
0 All the elements in an array have the same data type.
(For example all integers, all Strings, all doubles and so on)
Examples:
int [] x; //x is an array of integers.
double [] myArray; //myArray is an array of doubles.

8. Creating Arrays
0 The size if an array is fixed. It is specified when the array is
created and cannot be changed (Abdennadher , 2010).
x = new int[5]; //array x is now of size 5
myArray = new double[3];

9. Creating Arrays
0 An array can be declared and created in one statement.
0 Until this point the arrays is empty (contains default values
of its declared type)
Examples:
int [] x = new int [5];
double [] myArray = new double [3];
int number = 10;
char [] letters = new char[number];

10. Initializing Arrays
Double [] prices = new double [5];

11. Initializing Arrays
Double [] prices = {2.25, 3.0, 10.5, 5.3, 0.5};
2.25
3.0
10.5
5.3
0.5

12. Using Arrays
After creating and initializing an array, it can be used
within a program:
• An element in the array can be used within a
statement
• The reference to the array can be used within a
statement. (Abdennadher , 2010)

13. Using Arrays
0 Reassign value to index:
4.5
2.25
Prices[0] = 4.5;
3.0
10.5
5.3
0.5
0 Using element within a statement:
if(Prices[1] >= 3.0){
Discount = 10;
}

14. Array Examples
0 Write a java program that creates an array of size 3 and
prints all its elements using a for loop.

16. References
• Abdennadher S. (2010). Arrays. Lecture notes.
• Eckert T. (2009). Bimaru - Battleship Solitaire [image]. Retrieved from:
http://www.cyrket.com/p/android/com.androidcan.bimaru/
• Mughal K. A. & Rasmussen R. W. (2009). A Programmer's Guide to Java SCJP
Certification. Upper Saddle River, NJ: Pearson Education.
• Neuroph (2012). Image colors [image]. Retrieved from: http://
neuroph.sourceforge.net/image_recognition.html
• Oracle (2012). An array of 10 elements [image]. Retrieved from: http
://docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html