BINARY_SEARCH

//program that take an array input from user and finding key using Binary Search.
import java.util.*;
public class BINARY_SEARCH {
    public static int BinarySEARCH(int arr[], int key){
        int start = 0;
        int end = arr.length - 1;
        while(start<=end){
            int mid = (start+end)/2;
            if(arr[mid]==key){
                return mid;
            }
            if(arr[mid] < key){
                start = mid+1;
            } else {
                end = mid-1;
            }
        }
        return -1;
    }
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a value : ");
        int n = sc.nextInt();
        int arr[] = new int[n];
        System.out.println("Enter array element : ");
        for(int i=0; i<arr.length; i++){
            arr[i] = sc.nextInt();
        }
        System.err.print("Enter key value : ");
        int key = sc.nextInt();
        int index = BinarySEARCH(arr, key);
        if(index == -1){
            System.out.println("Key not found.");
        } else {
            System.out.println(key+" found at "+index+"th index.");
        }

    }
}