From 94f3ffe146f7f2daa4a8c4e8498d587e6ee27876 Mon Sep 17 00:00:00 2001
From: Krishna Vedala <krishna.vedala@ieee.org>
Date: Thu, 28 May 2020 19:37:33 -0400
Subject: [PATCH] document binary search

---
 search/binary_search.cpp | 56 +++++++++++++++++++++++++++-------------
 1 file changed, 38 insertions(+), 18 deletions(-)

diff --git a/search/binary_search.cpp b/search/binary_search.cpp
index d8a3a6631..66da31d7f 100644
--- a/search/binary_search.cpp
+++ b/search/binary_search.cpp
@@ -1,35 +1,55 @@
+/**
+ * @file
+ * @brief [Binary search
+ * algorithm](https://en.wikipedia.org/wiki/Binary_search_algorithm)
+ */
 #include <iostream>
-// binary_search function
-int binary_search(int a[], int l, int r, int key) {
+
+/** binary_search function
+ * \param [in] a array to sort
+ * \param [in] r right hand limit = \f$n-1\f$
+ * \param [in] key value to find
+ * \returns index if T is found
+ * \return -1 if T is not found
+ */
+int binary_search(int a[], int r, int key) {
+    int l = 0;
+
     while (l <= r) {
-          int m = l + (r - l) / 2;
-          if (key == a[m])
-              return m;
-          else if (key < a[m])
-               r = m - 1;
-          else
-              l = m + 1;
-          }
-          return -1;
-     }
+        int m = l + (r - l) / 2;
+        if (key == a[m])
+            return m;
+        else if (key < a[m])
+            r = m - 1;
+        else
+            l = m + 1;
+    }
+    return -1;
+}
+
+/** main function */
 int main(int argc, char const* argv[]) {
     int n, key;
     std::cout << "Enter size of array: ";
     std::cin >> n;
     std::cout << "Enter array elements: ";
+
     int* a = new int[n];
-// this loop use for store value in Array
+
+    // this loop use for store value in Array
     for (int i = 0; i < n; i++) {
         std::cin >> a[i];
-        }
+    }
+
     std::cout << "Enter search key: ";
     std::cin >> key;
-// this is use for find value in given array
-    int res = binary_search(a, 0, n - 1, key);
+
+    // this is use for find value in given array
+    int res = binary_search(a, n - 1, key);
     if (res != -1)
-       std::cout << key << " found at index " << res << std::endl;
+        std::cout << key << " found at index " << res << std::endl;
     else
-       std::cout << key << " not found" << std::endl;
+        std::cout << key << " not found" << std::endl;
 
     delete[] a;
     return 0;