One Dimension Array in Java language

One Dimension Array in Java language

In this tutorial, we will discuss One Dimension Array in Java language

Introduction of Array

The array is a  data type in Java, which is the collection of similar type of element that has contiguous memory location, That is similar to a table of an object or primitive data type. We can store an Only fixed set of similar element in java array.

 

Advantages of java array

• Code optimization – it makes the code optimized, We can retrieve or short the data easily
• Random access – We can get any data located any index position
• It is used to represent multiple data items of similar type by using a single name
• It can be used to implement other data structure similar Stacks, queues, Linked list, trees, graphs

Array declaration, creation, initialization        

Declaration of single Dimension Array in Java

When using an array in a program, you must declare a variable to reference the array
You must specify the type of array when the variable can reference

Syntax

dataType[] array_name;
dataType []array_name;
dataType array_name[];

example

int[] number;
int []number;
int number[];

double[] zscore;
double []zscore;
double zscore[];

String[] name;
String []name;
String name[];

The default value of an array in Java

When we array is declared, the array will be filled by 0 of every array index in the memory location

The default value is zero for numeric type

the default value of the string “null”

the default value of boolean”false”

Example

In this program, when we declare a one-dimensional array in java language(not initialized), Every array index is filled by zero – zero is a default value for integer data type

class ArrayDefaultValue{
public static void main(String args[]){
int[]marks=new int[10];//array is declared

for(int i=0; i<10; i++){
System.out.println("value of array index "+i+" is :"+marks[i]);

}
}

}

When the above code executed it produces the following output

Creation of single Dimension Array in Java

arrayname=new datatype[array length];

Example

number=new int[4];

Diclaration and Creation in one line

Syntax

datatype []arrayname=new datatype[array length];

Example

int [] number=new int[4];

 

initialization  of single Dimension Array in Java

1. initialization – using the standard method
   
   

here, we can initialize the array element to each cell at a time

initialize one by one

Array

program 1 – int array

class Array2{

public static void main(String []args){
int[] x;                   //Declaration of single Dimention Array in Java

x=new int[5];          //Creation of single Dimention Array in Java

//initialitation  of single Dimention Array in Java

x[0]=10;              //..first element
x[1]=5;
x[2]=7;
x[3]=8;
x[4]=22;         //fifth element

System.out.println (x[4]);             //Display the element index of 4
}

}

out put 22

When the above code executed it produce following output

 

2. initialization – During the declaration

Syntax

type[]arrayName={List of element seperated by comma};

Example

char[]alphabets={a,b,c,d,e,f,g};

Program 1

class Array_SumAvg{
public static void main(String args[]){
double height[]={67.5,87.6,98.1,56.0,45.54,98.97,77.34,43.5,35.7,51.43};
double sum=0;
for(double h:height)
sum+=h;
double avg=sum/10;
avg=sum/10;

System.out.println("Average height of 10 student :"+avg );

}

}

When the above code executed it produce following output

Average height of 10 student :66.168

 

initialization and retrieve elements- using loops with Scanner class

Using for loop

Initialize element using for loop(code segment)

for(i=0; i<array.length; i++){
array.length[i]=myObj.next.Int();
}

 

 display of element using for loop(code segment)

for(i=0; i<array.length; i++){
System.out.print(arrName[i]+" ");
}

Program

import java.util.Scanner;
class ArrayWithFor1{
public static void main (String args[]){
int arr_Len;
Scanner scan=new Scanner(System.in);
System.out.print("Enter Array length: ");
arr_Len=scan.nextInt();
int arr[]=new int[arr_Len];
System.out.print("\nEnter "+arr_Len+" Element to array: \n");
for(int i=0; i<arr_Len; i++){
arr[i]=scan.nextInt();
}
System.out.print("\nDisplay element from array\n");
for(int i=0; i<arr_Len; i++){
System.out.print(arr[i]+" ");
}
}
}

When the above code executed it produces the following output

 

Using while loop

Initialize element using while loop(code segment)

i=0; 
while(i<array.length){
array.length[i]=myObj.next.Int();
 i++;
}

 

display element using while loop(code segment)

i=0;
while(i<array.length){
System.out.print(arrName[i]+" ");
i++;
}

 

 

Example

import java.util.Scanner;
class ArrayWithWhile1{
public static void main (String args[]){
int arr_Len;
Scanner scan=new Scanner(System.in);
System.out.print("Enter Array length: ");
arr_Len=scan.nextInt();
int arr[]=new int[arr_Len];
System.out.print("\nEnter "+arr_Len+" Element to array: \n");
int i=0;
while(i<arr_Len){
arr[i]=scan.nextInt();
i++;
}
System.out.print("\nDisplay element from array\n");
i=0;
while(i<arr_Len){
System.out.print(arr[i]+" ");
 i++;
}
}
}

When the above code executed it produces the following output

Using the do-while loop

Initilize element using do-while loop(code segment)

i=0;
do{
array.length[i]=myObj.next.Int();
i++;
}while(i<array.length);

 

display element using do-while loop(code segment)

i=0;
do{
System.out.print(arrName[i]+" ");
i++;
}while(i<array.length);

 

Example

import java.util.Scanner;
class ArrayWithDoWhile1{
public static void main (String args[]){
int arr_Len;
Scanner scan=new Scanner(System.in);
System.out.print("Enter Array length: ");
arr_Len=scan.nextInt();
int arr[]=new int[arr_Len];
System.out.print("\nEnter "+arr_Len+" Element to array: \n");
int i=0;
do{
arr[i]=scan.nextInt();
i++;
}while(i<arr_Len);
System.out.print("\nDisplay element from array\n");
i=0;
do{
System.out.print(arr[i]+" ");
 i++;
}while(i<arr_Len);
}
}

When the above code executed it produces the following output

 

Using Enhanced for loop – retrieve elements from the array

for(int x:arr){
System.out.print(x+" ");
}

Example

import java.util.Scanner;
class ArrayWithForEach1{
public static void main (String args[]){
int arr_Len;
Scanner scan=new Scanner(System.in);
System.out.print("Enter Array length: ");
arr_Len=scan.nextInt();
int arr[]=new int[arr_Len];
System.out.print("\nEnter "+arr_Len+" Element to array: \n");
for(int i=0; i<arr_Len; i++){
arr[i]=scan.nextInt();
}
System.out.print("\nDisplay element from array\n");
for(int x:arr){
System.out.print(x+" ");
}
}
}

When the above code executed it produces the following output

Examples

program 1- 

display one d array element using single for loop

class Array3{

public static void main(String []args){
int[] x;
x=new int[5];
x[0]=10;
x[1]=5;
x[2]=7;
x[3]=8;
x[4]=22;

for(int i=1; i<=5;i++){
System.out.println (x[i]);
}

}

}

When the above code executed it produces the following output

5
7
8
23

Program 2

display one d array element using single Enhanced for loop

class Array3{

class array_foreach{
public static void main(String []args){
int[] x;
x=new int[5];
x[0]=10;
x[1]=5;
x[2]=7;
x[3]=8;
x[4]=22;

for(int i:x){
System.out.println (i);
}

}
}

 

Program 3

class Arraydemo{
public static void main(String []args){
int[] anArray;
anArray=new int[10];
anArray[0]=100;
anArray[1]=200;
anArray[2]=300;
anArray[3]=400;
anArray[4]=500;
anArray[5]=600;
anArray[6]=700;
anArray[7]=800;
anArray[8]=900;
anArray[9]=1000;

System.out.println(“Element at index 0:”+(anArray[0]));
System.out.println(“Elemeny at index 1:”+(anArray[1]));
System.out.println(“Element at index 2:”+(anArray[2]));
System.out.println(“Elemeny at index 3:”+(anArray[3]));
System.out.println(“Element at index 4:”+(anArray[4]));
System.out.println(“Elemeny at index 5:”+(anArray[5]));
System.out.println(“Element at index 6:”+(anArray[6]));
System.out.println(“Elemeny at index 7:”+(anArray[7]));
System.out.println(“Element at index 8:”+(anArray[8]));
System.out.println(“Elemeny at index 9:”+(anArray[9]));
}
}

When the above code executed it produces the following output

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