Verify Element Existence in Array using Java

Given an array and one of its element as an input, write a Java program to check whether that element exists in given array or not. You can find any element from an array using search algorithms. In this article, we will use linear search and binary search algorithms.

Using Linear Search Algorithm

In this approach, follow the steps below to verify whether a given element exists in an array ?

• Iterate through the array using for loop.
• Compare each element with the required element.
• If found return the index.

Example

The following Java program shows how to check whether a given element exists in an array using linear search algorithm.

import java.util.*;
public class ArraySearch {
   public static void main(String[] args) {
      int[] myArray = {23, 93, 56, 92, 39};
      System.out.println("Elements of the given array: " + Arrays.toString(myArray));
      int searchVal = 39;
      System.out.println("The value to be searched: " + searchVal);
      // checking if the element is present
      for (int i =0 ; i < myArray.length; i++) {
         if (myArray[i] == searchVal) {
            System.out.println("The index of element " + searchVal + " is : " + i);
         }
      }
   }
}

When you execute this code, following output will be displayed ?

Elements of the given array: [23, 93, 56, 92, 39]
The value to be searched: 39
The index of element 39 is : 4

Using Arrays.binarySearch() method

The Arrays class of the java.util package provides a method with name binarySearch(), this method accepts a sorted array and a value to search and returns the index of the given element in the array.

Example

In this example, we use the binarySearch() method to verify whether a given element exists in an array.

import java.util.Arrays;
import java.util.Scanner;
public class ArraySearch {
   public static void main(String[] args) {
      int[] myArray = {23, 93, 56, 92, 39};
      System.out.println("Elements of the given array: " + Arrays.toString(myArray));
      int searchVal = 39;
      System.out.println("The value to be searched: " + searchVal);
      //Sorting the array
      Arrays.sort(myArray);
      System.out.println("The sorted int array is:");
      for (int number : myArray) {
         System.out.print(number+" ");
      }
      System.out.println(" ");
      int retVal = Arrays.binarySearch(myArray,searchVal);
      System.out.println("Element found");
      System.out.println("The index of element in the sorted array: " + retVal);
   }
}

On running the above code, it will show the following result ?

Elements of the given array: [23, 93, 56, 92, 39]
The value to be searched: 39
The sorted int array is:
23 39 56 92 93  
Element found
The index of element in the sorted array: 1