Binary Search in Array
This program performs binary search to find an element in a sorted array.
Problem Statement
Write a Java program to search for a given element in a sorted integer array using binary search.
Source Code
| 1 | public class BinarySearch { |
| 2 | public static void main(String[] args) { |
| 3 | int[] arr = {5, 10, 15, 20, 25, 30}; |
| 4 | int key = 20; |
| 5 | int low = 0, high = arr.length-1; |
| 6 | boolean found = false; |
| 7 | while(low <= high) { |
| 8 | int mid = (low + high)/2; |
| 9 | if(arr[mid] == key) { |
| 10 | System.out.println("Element found at index: " + mid); |
| 11 | found = true; |
| 12 | break; |
| 13 | } else if(arr[mid] < key) low = mid+1; |
| 14 | else high = mid-1; |
| 15 | } |
| 16 | if(!found) System.out.println("Element not found"); |
| 17 | } |
| 18 | } |
Program Output
Element found at index: 3
Explanation
The array must be sorted, and variables low, high, and mid control the search boundaries: if arr[mid] equals key it's found, if smaller the search continues right, if larger it continues left, demonstrating the binary search algorithm.