Added Comments

Author: Vaidehi0421

Diff for: code/search/src/binary_search/binary_search.java

@@ -2,48 +2,48 @@
  * Part of Cosmos by OpenGenus Foundation
 */
 class Search
-{
+{//Implementation of Binary Search in java
     static int recursiveBinarySearch(int arr[], int l, int r, int x)
-    {
+    {//recursive function that returns the index of element x if it is present in arr[],else returns -1
         if (r>=l)
         {
-            int mid = l + (r - l)/2;
+            int mid = l + (r - l)/2; //finding out the middle index
 
             if (arr[mid] == x)
-               return mid;
+               return mid; //If x is present at the middle
 
-            if (arr[mid] > x)
+            if (arr[mid] > x) //If x is smaller than the element at middle,then it might be present in the left of middle.
                return recursiveBinarySearch(arr, l, mid-1, x);
 
-            return recursiveBinarySearch(arr, mid+1, r, x);
+            return recursiveBinarySearch(arr, mid+1, r, x); //else the element can only be present in the right subarray
         }
-        return -1;
+        return -1; //-1 is returned if the element x is not present in the array
     }
 
     static int binarySearch(int arr[], int l, int r, int x)
-    {
-        while (l <= r)
+    {//Iterative implementation of Binary Search
+        while (l <= r) //the loop runs till the low index(l) is less than or equal to the high index(r)
         {
-            int mid = l + (r-l)/2;
+            int mid = l + (r-l)/2; //Calculating middle index
 
             if (arr[mid] == x) 
-                return mid;  
+                return mid;  //if the element x is present on middle index
 
-            if (arr[mid] < x) 
+            if (arr[mid] < x)  //If x greater, ignore left half
                 l = mid + 1; 
 
             else
-                r = mid - 1; 
+                r = mid - 1; // If x is smaller, ignore right half 
         }
-        return -1; 
+        return -1; //if the element is not present in the array,-1 is returned
     }
 
     public static void main(String args[])
     {
         int arr[] = {1, 2, 3, 5};
-        int size = arr.length;
-        int find = 3;
+        int size = arr.length; //stores the length of arr[]
+        int find = 3; //Element to be searched
         System.out.println("Position of "+find+" is "+recursiveBinarySearch(arr,0,size-1,find));
         System.out.println("Position of "+find+" is "+binarySearch(arr,0,size-1,find));
     }
-}
+}