Java Programing laungage

Core Java Tutorial

Introduction of Core Java

How To Install JDk and Set of Path

Syntax of java Program

Difference between Java and C/C++

Advantage and Disadvantage of Java

What is Java

Why Java is not Pure Object Oriented Language

Java has Following Features/Characteristics

Limitation of Java Language and Java Internet

Common Misconception about Java

Simple Program of Java

Integrated Development Environment in java

Compile and Run Java Program

Applet and Comments in Java

Tokens in Java

Keywords in Java

Identifier and Variables in Java

Literals/Constants

Data Type in Java

Assignments and Initialization in Java

Operators in Java

Rule of Precedence in Java

Operator on Integer and Separators in Java Programming

Java Control Flow of Statements

If and If-else Selection Statement

Nested If-else and If-else-If Selection Statement

switch case and conditional operator Selection Statement

for and while Loop

do..while and for each Loop

break and labeled break statement

continue and labeled continue statement

return Statement and exit() Method

Escape Sequence for Special Characters and Unicode Code

Constants and Block or Scope

Statement in Java

Conversions between Numeric Types in Java

Import Statement in Java

User Input in Java using Scanner Class

User Input in Java using Console Class

Array in Java

One Dimensional Array

Two Dimensional Array

Two Dimensional Array Program

Command Line Argument in Java

String args Types in Java

Uneven/Jagged array in java

Math Class Function and Constant

Math Class all Function used in a program

Enumerated Types in Java

Object Oriented Programming v/s Procedural Programming

Object Oriented Programming Concepts in Java

Introduction to Class,Object and Method in Java

Class Declaration in Java

Class & Objects in java

Encapsulation in Java

Modifiers/Visibility for a Class or Interrface or member of a Class

Polymorphism in Java

Runtime polymorphism (dynamic binding or method overriding)

Arrays and Anonymous Arrays
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An array is a data structure that stores a collection of homogeneous(same type) values. You can access each individual value of the array through an integer index.

For Example: If arr is an array of integers, then arr[i] is the ith integer in the array. You can declare an array variable by specifying the array type which is the element type followed by [] and the array variable name. Now we can delare an array variable arr as


int[] arr;    //please prefer this one
or
int arr[];

Above statement only declares the variable arr. It doesn't intiailize the arr with an actual array, for that we have to use new operator to declare an array. For instance,


int[] arr = new int[50];

Above declaration creates an array of integer type which can accomodate 50 integers. In Java too, like other programming languages, the index of array starts from 0 to (length-1). In this case array enteries are numbered from 0 to 49. Also Java doesn’t allow you to specify the size of an empty array when declaring the array.

You always must explicitly set the size of the array with the new operator or by assigning a list of items to the array on creation. If you try to access the element arr[50] (or any other index outside the range 0 ..49), then your program will terminate with an “array index out of bounds” exception. As in other languages like C and C++ once you create an array, you cannot change its size.

Anonymous Arrays

Java can directly create an array object and supply initial values at the same time just like other languagaes. For e.g.

  • int[] numbers = { 2, 3, 4, 5, 6, 7, 8 };

You do not call new when you declare an array using this approach.You can even initialize an anonymous array in java like the following one:

  • new int[] { 11, 12, 13, 14, 15, 16, 17};

Above declaration allocates a new array and fills it with the values inside the braces and counts the number of initial values then sets the array size accordingly. You can use this syntax to reinitialize an array without creating a new variable.

Example


numbers = new int[] { 11, 12, 13, 14, 15, 16, 17 };
is a shorthand for
int[] anonymousarr = { 11, 12, 13, 14, 15, 16, 17 };
numbers = anonymousarr;

Once an array is created you can access its elements throught its index values.For calculating the length of an array we use length() method viz. arrayname.length, gives the length of the array. Following code snippet shows the very same:


Java Tutorialslass ArrayAccess
{
  public static void main(String[] args)
   {
     int[] numbers={2, 3, 4, 5, 6, 7, 8};
     System.out.println("The elements of the array are :");
      for(int i=0;i<numbers.length;i++)
      {
        System.out.println(a[i]);
      }
   }
}

Here, we have use numbers. length to calculate the length of the array and a[i] gives the elements of the array.

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