Binary Search — runnable Java

Runnable Java file — no imports, no Maven needed. Save it and run java binarysearch.java.

import java.util.Scanner;

public class binarysearch {
    // Function to perform binary search on a sorted array
    public static int binarySearch(int[] arr, int key) {
        int left = 0, right = arr.length - 1;
        while (left <= right) {
            int mid = left + (right - left) / 2;
            if (arr[mid] == key)
                return mid; // Key found at index mid
            else if (arr[mid] < key)
                left = mid + 1;
            else
                right = mid - 1;
        }
        return -1; // Key not found
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        // Input: size of the array
        System.out.print("Enter the number of elements in the array: ");
        int n = sc.nextInt();
        int[] arr = new int[n];

        System.out.println("Enter " + n + " sorted integers:");
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }

        System.out.print("Enter the number to search: ");
        int key = sc.nextInt();

        int result = binarySearch(arr, key);

        if (result == -1)
            System.out.println("Element not found in the array.");
        else
            System.out.println("Element found at index: " + result);
        
        sc.close();
    }
}