Write a Java Program to Perform Binary Search in a Sorted Array

Description

Binary search is one of the famous and fundamental algorithm in computer science which solves a large number of problems in developing applications and APIs. It uses divide and conquer approach to find out the element.Here, we will be writing a sample program in java that implements binary search.The given array is a sorted array of n elements and we have to search the position a given element inside the array.

public class SampleBinarySearch {

	public int binarySearch(int[] arr, int key) {

		int start = 0;
		int end = arr.length - 1;
		while (start <= end) {
			int mid = (start + end) / 2;
			if (key == arr[mid]) {
				return mid;
			}
			if (key < arr[mid]) {
				end = mid - 1;
			} else {
				start = mid + 1;
			}
		}
		return -1;
	}

	public static void main(String[] args) {

		SampleBinarySearch sbs = new SampleBinarySearch();
		int[] arr = { 2, 4, 6, 8, 10, 12, 14, 16 };
		System.out.println("Key 14's position: " + sbs.binarySearch(arr, 14));
		int[] arr1 = { 6, 34, 78, 123, 430, 900 };
		System.out.println("Key 430's position: " + sbs.binarySearch(arr1, 430));
	}
 }

Worst case performance: O(log n)

Best case performance: O(1)