binaryu search code example

Example 1: binary search

import java.util.Scanner;

public class Binarysearch {

	public static void main(String[] args) {
		int[] x= {1,2,3,4,5,6,7,8,9,10,16,18,20,21};
		Scanner scan=new Scanner(System.in);
		System.out.println("enter the key:");
		int key=scan.nextInt();
		int flag=0;
		int low=0;
		int high=x.length-1;
		int mid=0;
		while(low<=high)
		{
			mid=(low+high)/2;
			if(key<x[mid])
			{
				high=mid-1;
			}
			else if(key>x[mid])
			{
				low=mid+1;
			}
			else if(key==x[mid])
			{
				flag++;
				System.out.println("found at index:"+mid);
				break;
			}
		}
		if(flag==0)
		{
			System.out.println("Not found");
		}
		

	}

}

Example 2: binary search

//it is using divide and conquer method
#include <iostream>

using namespace std;
void binarysearch(int arr[],int start,int end,int val)
{
    if(start<end)
    {
        int mid=(start+end)/2;
        if(arr[mid]==val)
        {
            cout<<"value found:"<<endl;
        }
        else if(arr[mid]<val)
        {
            binarysearch(arr,mid+1,end,val);
        }
        else if(arr[mid]>val)
        {
            binarysearch(arr,start,mid-1,val);
        }
    }
    else
    {
        cout<<"not present:"<<endl;
    }
}

int main()
{
    int n;
    cout<<"enter the size of the array:"<<endl;
    cin>>n;
    int arr[n];
    cout<<"enter the elements of the array:"<<endl;
    for(int i=0;i<n;i++)
    {
        cin>>arr[i];
    }
    cout<<"enter the value you want to search:"<<endl;
    int val;
    cin>>val;
    binarysearch(arr,0,n-1,val);

    return 0;
}