Find/search element in sorted integer array (java/binary search algorithm/iterative)

1. Given sorted integer array in java.
2. Find or search element/integer in an array using binary search algorithm (with example).
3. Binary search is a divide and conquer algorithm.
   • Binary search algorithm is used to find element in sorted arrays.
4. We have already discussed about find element in a sorted integer array using binary search algorithm(recursive).
   • We had discussed in detail about binary search algorithm using java.
   • Recursive post is kind of prerequisite for current post.
5. Arrays class in java also has predefined binary search function.
   • We have demonstrated its sample code as follows.

int arr[] = {10,20,30,40,50,60,70,80,90,100};
System.out.println(Arrays.binarySearch(arr, 70));
//Output is: 6

1. Find/search element in sorted integer array in java (binary search algorithm)

package org.learn.arrays;

import java.util.Arrays;

public class BinarySearchIterative {
 public static void main(String[] args) {
  int arr[] = {10,20,30,40,50,60,70,80,90,100};
  //low index
  int low = 0;
  //high index
  int high = arr.length - 1;
  int search = 70;
  int result = binarySearch(arr, search, low, high);
  if(result == -1) {
   System.out.printf("1. Element %d not found in array",search);   
  } else {
   System.out.printf("1. Element %d found at index : %d ",search,result);
  }
  System.out.println("");
  
  search = 60;
  result = binarySearch(arr, search, low, high);
  if(result == -1) {
   System.out.printf("2. Element %d not found in array",search);   
  } else {
   System.out.printf("2. Element %d found at index : %d",search,result);
  }
  System.out.println("");
  
  search = 110;
  result = binarySearch(arr, search, low, high);
  if(result == -1) {
   System.out.printf("3. Element %d not found in array",search);   
  } else {
   System.out.printf("3. Element %d found at index : %d",search,result);
  }
  System.out.println("");
 }

 private static int binarySearch(int[] arr, int value, int low, int high) {
 
  while (low <= high) {
   int middle = low + (high - low) / 2;
   if (value < arr[middle]) { // search between low ---> middle
    high = middle - 1;
   } else if (value > arr[middle]) {
    // search in upper half middle + 1 -----> high
    // low to middle already covered in first case
    // so start search from middle + 1 to high here...
    low = middle + 1;
   } else {
    // value == arr[middle]
    // yes we got the element in binary search tree
    return middle;
   }
  }
  return -1;
 }
}

2. Find/search element in sorted integer array (java/binary search algorithm)

1. Element 70 found at index : 6
2. Element 60 found at index : 5
3. Element 110 not found in array