BinarySearch.java

import java.util.*;
class BinarySearch{  
 public static void main(String args[]){  
    int numArray[] = {5,10,15,20,25,30,35}; 
    System.out.println("The input array: " + Arrays.toString(numArray));
    //key to be searched
    int key = 20;
    System.out.println("\nKey to be searched=" + key);
    //set first to first index
    int first = 0;
    //set last to last elements in array
    int last=numArray.length-1; 
    //calculate mid of the array
    int mid = (first + last)/2;  
    //while first and last do not overlap
    while( first <= last ){  
        //if the mid < key, then key to be searched is in the first half of array
        if ( numArray[mid] < key ){  
            first = mid + 1;     
        }else if ( numArray[mid] == key ){ 
            //if key = element at mid, then print the location
            System.out.println("Element is found at index: " + mid);  
            break;  
        }else{  
            //the key is to be searched in the second half of the array
            last = mid - 1;  
        }  
        mid = (first + last)/2;  
   }  
   //if first and last overlap, then key is not present in the array
   if ( first > last ){  
      System.out.println("Element is not found!");  
   }       
 }  
}