One dimensional array in java with examples

Here we will discuss One dimensional array in java and cover basic examples

What is One dimensional (Single dimensional) array in java

An array is a collection of similar elements. All array elements are stored in the contiguous memory location.

One dimensional or single-dimensional array is an array with one dimension.

One dimensional array declaration in java

Syntax

    type arrayname[];
   Or type [] array name;

Example

int [] age;//collection of integer elements
float[] price;// collocation of float elements;
String [] names;// collocation of string element;

In the above declaration, age is a reference variable that will hold reference of array same for price and for names.

One dimensional array construction

The array uses a new operator to dynamically allocate memory locations.
Syntax

    Array name= new type [size];

Example

age=new int[5];
price=new float[5];
names=new String[10];

the new operator will dynamically allocate memory for 5 integer values that are 5*4=20 bytes continuously.

The array uses zero-based indexing where the first element is stored in a zero location. The last element is stored in the array size-1 location.

We can assign values in array elements one by one as below

age[0]=21;
age[1]=43;
age[2]=34;
age[3]=37;
age[4]=55;

Single dimensional array initialization in java

Array declaration and initialization can be done in one statement
syntax

type[] array name = {value,value,…..value};

Example

int[] age= {21,43,34,37,55}

Accessing array element: array element can be accessed by its index value.

Syntax

arrayName[indexExpression];

For example age[0] access all first value of the array we can use a loop
We can print all values in age below

One dimensional array in java examples

 public class MyClass {
    public static void main(String args[]) {
     double[]  price={22.33,44.22,55.66,33.66,77.11};
     for(int i=0;iprice[0]=22.33
price[1]=44.22
price[2]=55.66
price[3]=33.66
price[4]=77.11

Array programs in java

public class FirstArray {

    public static void main(String[] s) {
        int[] age = new int[5];
        age[0] = 21;
        age[1] = 23;
        age[2] = 45;
        age[3] = 31;
        age[4] = 33;
        for (int i = 0; i < 5; i++) {
            System.out.println("age[" + i + "]= " + age[i]);
        }

    }
}

Result

age[0]= 21
age[1]= 23
age[2]= 45
age[3]= 31
age[4]= 33

We can also use for each loop to show array elements

Java array programs

public class JavaArray {

    public static void main(String[] s) {
        int[] age = new int[5];
        age[0] = 21;
        age[1] = 23;
        age[2] = 45;
        age[3] = 31;
        age[4] = 33;
        for (int a : age) {
            System.out.println("age= " + a);
        }

    }
}

Output

 
age= 21
age= 23
age= 45
age= 31
age= 33

Array input in java

The scanner class is used here to get Input in the array.

import java.util.Scanner;
public class ArrayInputByUser {
    public static void main(String[] args) {
        int[] age = new int[5];
        System.out.println("Enter  age to save in array");
        Scanner sc = new Scanner(System.in);
        for (int i = 0; i < 5; i++) {
            System.out.print("age[" + i + "]= ");
            age[i] = sc.nextInt();
        }
        System.out.println("Age array values are");
        for (int i = 0; i < 5; i++) {
            System.out.println("age[" + i + "]= " + age[i]);
        }
    }
}

 
Enter  age to save in array
age[0]= 4
age[1]= 5
age[2]= 6
age[3]= 7
age[4]= 4
Age array values are
age[0]= 4
age[1]= 5
age[2]= 6
age[3]= 7
age[4]= 4

Static array in java

To create a static array add the keyword static before an array.

public class StaticArrayExample {

    static final String[] EMAILS = {"[email protected]", "[email protected]", "[email protected]"};

    public static void main(String[] args) {
        for (String s : EMAILS) {
            System.out.println(s);
        }

    }

}

 
[email protected]
[email protected]
[email protected]

Length of array in java

the length property of an array is used to find the length of an array

public class MyClass {
    public static void main(String args[]) {
     String[]  names={"Ram","Mohan","Sohan","Rita","Meeta","Geeta"};
           System.out.println("Total names are "+names.length );
     }
}

 
Total names are 6

How to store string in array in java

public class MyClass {
    public static void main(String args[]) {
        String[] names = {
            "Ram",
            "Mohan",
            "Sohan",
            "Rita",
            "Meeta",
            "Geeta"
        };
        System.out.println("Names are ");
        for (int i = 0; i < names.length; i++) {
            System.out.println(names[i]);
        }
        String[] branch = new String[5];
        branch[0] = "Computer Science & Engineering";
        branch[1] = "Mechanical Engineering";
        branch[2] = "Civil Engineering";
        branch[3] = "Electronics and Telecomm Engineering";
        branch[4] = "Information Technology";
        System.out.println("Branches are");
        for (String s: branch) {
            System.out.println(s);
        }
    }
}

 
Names are 
Ram
Mohan
Sohan
Rita
Meeta
Geeta
Branches are
Computer Science & Engineering
Mechanical Engineering
Civil Engineering
Electronics and Telecomm Engineering
Information Technology

String to integer array in java

public class StringtoIntArray {
    public static void main(String[] args) {
        String s1 = "[1,2,3,4,5,6,7,8,9]";
        System.out.println("String is "+s1);
        StringTokenizer s2 = new StringTokenizer(s1, "[,] ");
        int length = s2.countTokens();
        int[] intArray = new int[length];
        int i=0;
        while (s2.hasMoreTokens()) {
            intArray[i]=Integer.parseInt(s2.nextToken());
            i++;
        }
        System.out.println("Integer Array is ");
        for (int j = 0; j < intArray.length; j++) {
            System.out.println("intArray["+j+"] = "+intArray[j]);
            
        }
    }
}

This program is taking a string as an argument converting it to StringTokenizer based on delimiter [,] and space.

A string tokenizer contains a set of string tokens these tokens are converted to an integer using Integer.parseInt().

above program can handle the following strings

String s1 = "1 2 3 4 5 6 7 8 9"; or

String s1 = "1,2,3,4,5,6,7,8,9";

String s1 = "[1,2,3,4,5,6,7,8,9]";

String is [1,2,3,4,5,6,7,8,9]
Integer Array is 
intArray[0] = 1
intArray[1] = 2
intArray[2] = 3
intArray[3] = 4
intArray[4] = 5
intArray[5] = 6
intArray[6] = 7
intArray[7] = 8
intArray[8] = 9

Anonymous array in java

anonymous arrays in java are arrays without a name

like

new Integer[]{1, 2, 3, 4, 5, 6, 7}

new String[]{"Ram","Mohan","Sohan"};

public class AnonymousArray {

    public static void printArray(Integer[] arr) {
        for (Integer a : arr) {
            System.out.print(" "+a);
        }
    }

    public static void main(String[] args) {
        AnonymousArray.printArray(new Integer[]{1, 2, 3, 4, 5, 6, 7});
       
    }

}