Java Array
Java array is wrapper class in java which is used to store same type of data in a sequence or list, for example if we want to store names of 10 people we can use string type array to hold list of name.
- Array stores multiple same type of data in an index.
- Array index starts with 0 and ends with total length of array -1.
Syntaxes of Java Array
Declaration of Array
<Array type>[] <name of array>;Initialization of Array
<array variable> = new datatype[size]; Example of Array
public class JavaArrayExample {
public static void main(String[] args) {
String[] strArray; //declaration of array
strArray = new String[5]; // Initialization of string array
strArray[0] = "John";
strArray[1] = "Meena";
strArray[2] = "Mr Tesla";
strArray[3] = "Sandy";
strArray[4] = "Rax";
System.out.println("0 index array element value = "+strArray[0]);
//declaration and initialization with size in one line
String[] strArray2 = new String[5];
}
} Output
0 index array element value = John
Types Of Array
Single dimensional array
Single dimensional array stores one type of data element in sequence.
Syntax of Single Dimensional Array
<Array data type>[] <name of array> = new datatype[size]; Example of Single Dimensional Array
public class JavaArrayExample {
public static void main(String[] args) {
    int[] intArray = new int[3]; //single dimensional array
    intArray[0] = 10;
    intArray[1] = 11;
    intArray[2] = 12;
    System.out.println("0 index array element value = "+intArray[0]);
}
} Output
0 index array element value = 10 Multidimensional Array
Multi-dimensional array stores one type of data element in multiple sequence.
Syntax of Multidimensional Array
[][] arrayVatiableName = new Data type[size][size];
This syntax will create two dimensional array or multidimensional array, see carefully the rectangular [] braces by using 1 we create single dimensional, by using more than 1 we create multidimensional arrays.
Example of Multidimensional Array
public class JavaArrayExample {
public static void main(String[] args) {
int[][] intArray = new int[3][3]; //multidimensional array
intArray[0][0] = 22;
intArray[0][1] = 11;
intArray[0][2] = 12;
intArray[1][0] = 10;
intArray[1][1] = 11;
intArray[1][2] = 12;
intArray[2][0] = 10;
intArray[2][1] = 11;
intArray[2][2] = 12;
System.out.println("[0][0] index array element value = "+intArray[0][0]);
}
} Output
[0][0] index array element value = 22
For Loop On Array
We can loop through any array and access each element.
Syntax
for( variable type: array name) {
}
Example
public class JavaArrayExample {
public static void main(String[] args) {
//Another way to create array of string
String[] names = { "Rax", "John", "Tom"};
//for each loop on array
for(String name: names){
System.out.println(name);
}
}
} Output
Rax
John
Tom
References
You may read more on oracle page: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html
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