added a one-line comment to tell what the library/header is for

sorting/selection_sort_recursive.c

@@ -4,11 +4,10 @@
  * @brief [Selection Sort](https://en.wikipedia.org/wiki/Selection_sort)
  * implementation using recursion.
  */
-#include <assert.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <time.h>
+#include <assert.h> /// for assert
+#include<stdio.h>   /// for IO operations
+#include <stdlib.h> /// for dynamic memory allocation
+#include <time.h>   /// for random numbers generation
 
 /**
  * @brief Swapped two numbers using pointer