package com.javajee.myBinarySearch;

public class BinarySearch {

    int [] Numbers= {1,2,3,4,5,6,7};
    int element=7;
    String result=null;
    
    public static void main(String[] args) {
        String rIndex;
        String iIndex;
        BinarySearch bl= new BinarySearch();
        
        int minIndex=0;
        int maxIndex=(bl.Numbers.length)-1;    
        //calling recursive search algorithm
        rIndex=bl.elemSearchRecurse(bl.Numbers,minIndex, maxIndex);
        //Calling iterative algorithm
        iIndex=bl.elemSearchIter(bl.Numbers, minIndex, maxIndex);
        System.out.println(rIndex);
        System.out.println(iIndex);
    }
    
    //Using Recursive algorithm
    
    public String elemSearchRecurse(int[] Array,int min, int max){
        
        if (max<min){
            result="value not found";            
        }
        else{
        int midIndex=midValueCalc(min, max);
        if(Array[midIndex]>element){
            elemSearchRecurse(Numbers, min, midIndex-1);
        }
        else if(Array[midIndex]<element){
            elemSearchRecurse(Numbers, midIndex+1, max);
        }
        else{
            result="index of element in recursive algorithm is"+midIndex;
        }
        }
        return result;
    }
    
    //Using Iterative algorithm
    
    public String elemSearchIter(int[] Array,int min, int max){
        String value=null;
        while(max>=min){
            int midIndex=midValueCalc(min, max);
            if (Array[midIndex]>element){
                max=midIndex-1;
            }
            else if(Array[midIndex]<element){
                min=midIndex+1;
            }
            else{
                value="Index of element found through iterative is"+midIndex;
                return value;
            }
        }
        
        return "ELEMENT NOT FOUND";
    }
    
    //mid index calculator
    
    public int midValueCalc(int min, int max){
        return (min+((max-min)/2));
    }
}
 

NOTE:

Binary search returns the index of searched element as result.

Element to be searched is compared with value of the middle element (mid) of the array.

if element=middle element, then index of middle element is returned as result.

if element < middle element, process continues with elements on the left side of the array. (sub array to the left)

if element > middle element, process continues with elements on the left side of the array. (sub array to the right)

This process continues until all elements are compared or when a match is found.

It can be done both recursively and iteratively.