Merge pull request #4465 from AJAYSHARMA2012/master

Added comments in binary.c file

Author: AdiChat

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

@@ -2,46 +2,64 @@
 /*
  * Part of Cosmos by OpenGenus Foundation
 */
+// A recursive binary search function. It returns 
+// location of x in given array arr[l..r] is present, 
+// otherwise -1 
 int recursiveBinarySearch(int arr[], int l, int r, int x)
 {
    if (r >= l)
    {
         int mid = l + (r - l)/2;
- 
+        // If the element is present at the middle 
+        // itself 
         if (arr[mid] == x)  
             return mid;
+        // If element is smaller than mid, then 
+        // it can only be present in left subarray
          if (arr[mid] > x) 
              return recursiveBinarySearch(arr, l, mid-1, x);
-       
+        // Else the element can only be present 
+        // in right subarray 
          return recursiveBinarySearch(arr, mid+1, r, x);
    }
+   // We reach here when element is not 
+   // present in array 
    return -1;
 }
-
+// A iterative binary search function. It returns 
+// location of x in given array arr[l..r] is present, 
+// otherwise -1 
 int binarySearch(int arr[], int l, int r, int x)
 {
   while (l <= r)
   {
     int mid = l + (r-l)/2;
-
+    // If the element is present at the middle 
+    // itself 
     if (arr[mid] == x) 
         return mid;  
-
+     // If element is greater than mid, then 
+    // it can only be present in right subarray
     if (arr[mid] < x) 
         l = mid + 1; 
-
+    // Else the element can only be present 
+    // in right subarray
     else
          r = mid - 1; 
   }
-  return -1; 
+   // We reach here when element is not 
+   // present in array 
+   return -1; 
 }
 
 int main(void)
 {
    int arr[] = {1, 2, 3, 5};
    int size = sizeof(arr)/ sizeof(arr[0]);
    int find = 3;
+   //Printing the position of element using recursive binary search
    printf("Position of %d is %d\n", find, recursiveBinarySearch(arr, 0, size-1, find));
+   //Printing the position of element using iterative binary search
    printf("Position of %d is %d\n", find, binarySearch(arr, 0, size-1, find));
    return 0;
-}
+}