Lecture 7 - Introduction to Array in JAVA | Declaration , Initialization and Accessing Array elemen смотреть онлайн

Lecture 7 - Introduction to Array in JAVA | Declaration , Initialisation and Accessing Array element in JAVA by Prateek Jain

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Array in java is a group of like-typed variables referred to by a common name. Arrays in Java work differently than they do in C/C++. Following are some important points about Java arrays.

In Java, all arrays are dynamically allocated. (discussed below)
Arrays are stored in contiguous memory [consecutive memory locations].
Since arrays are objects in Java, we can find their length using the object property length. This is different from C/C++, where we find length using sizeof.
A Java array variable can also be declared like other variables with [] after the data type.
The variables in the array are ordered, and each has an index beginning with 0.
Java array can also be used as a static field, a local variable, or a method parameter.
The size of an array must be specified by int or short value and not long.
The direct superclass of an array type is Object.
Every array type implements the interfaces Cloneable and java.io.Serializable.
This storage of arrays helps us randomly access the elements of an array [Support Random Access].
The size of the array cannot be altered(once initialized). However, an array reference can be made to point to another array.

An array declaration has two components: the type and the name. type declares the element type of the array. The element type determines the data type of each element that comprises the array. Like an array of integers, we can also create an array of other primitive data types like char, float, double, etc., or user-defined data types (objects of a class). Thus, the element type for the array determines what type of data the array will hold.

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The elements in the array allocated by new will automatically be initialized to zero (for numeric types), false (for boolean), or null (for reference types). Do refer to default array values in Java.


Obtaining an array is a two-step process. First, you must declare a variable of the desired array type. Second, you must allocate the memory to hold the array, using new, and assign it to the array variable. Thus, in Java, all arrays are dynamically allocated.

Accessing Java Array Elements using for Loop
Each element in the array is accessed via its index. The index begins with 0 and ends at (total array size)-1. All the elements of array can be accessed using Java for Loop.

Java Arrays
Normally, an array is a collection of similar type of elements which has contiguous memory location.

Java array is an object which contains elements of a similar data type. Additionally, The elements of an array are stored in a contiguous memory location. It is a data structure where we store similar elements. We can store only a fixed set of elements in a Java array.

Array in Java is index-based, the first element of the array is stored at the 0th index, 2nd element is stored on 1st index and so on.

Unlike C/C++, we can get the length of the array using the length member. In C/C++, we need to use the sizeof operator.