diff --git a/backtracking/subarray_sum.cpp b/backtracking/subarray_sum.cpp
index 3a4aa9e9c..bfd9ae27b 100644
--- a/backtracking/subarray_sum.cpp
+++ b/backtracking/subarray_sum.cpp
@@ -13,7 +13,7 @@
  */
 
 #include <cassert>        /// for assert
-#include <iostream>       /// for io operations
+#include <iostream>       /// for IO operations
 #include <unordered_map>  /// for unordered_map
 #include <vector>         /// for std::vector