Write a Java program to implement a Binary Search Algorithm.

Category : Java | Sub Category : Java Programs | By Runner Dev Last updated: 2021-04-19 14:38:11 Viewed : 152


It is a search algorithm that finds the position of a target value within a sorted array. Binary search compares the target value to the middle element of the array. Let’s now see how to implement a binary search algorithm.

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package runnerdev;
public class BinarySearch {
// Java implementation of recursive Binary Search
// Returns index of x if it is present in arr[l..
// r], else return -1
int binarySearch(int arr[], int l, int r, int x)
{
if (r >= l) {
int mid = l + (r - l) / 2;
// If the element is present at the
// middle itself
if (arr[mid] == x)
return mid;
// If element is smaller than mid, then
// it can only be present in left subarray
if (arr[mid] >x)
return binarySearch(arr, l, mid - 1, x);
// Else the element can only be present
// in right subarray
return binarySearch(arr, mid + 1, r, x);
}
// We reach here when element is not present
// in array
return -1;
}
public static void main(String args[])
{
BinarySearch ob = new BinarySearch();
int arr[] = { 2, 3, 4, 10, 40 };
int n = arr.length;
int x = 40;
int result = ob.binarySearch(arr, 0, n - 1, x);
if (result == -1)
System.out.println("Element not present");
else
System.out.println("Element found at index " + result);
}
}

On executing the above program, it will locate the element present at the particular index

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Element found at index 4

Search
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