From 6470f0318b1f741d53afb576f596df5fd617a9c2 Mon Sep 17 00:00:00 2001
From: Krishna Vedala <7001608+kvedala@users.noreply.github.com>
Date: Sun, 28 Jun 2020 15:18:52 -0400
Subject: [PATCH] fixed documentations

---
 .../binary_trees/threaded_binary_trees.c      |  4 +--
 machine_learning/adaline_learning.c           | 11 +++---
 machine_learning/kohonen_som_topology.c       | 15 ++++----
 machine_learning/kohonen_som_trace.c          | 36 +++++++++----------
 misc/cartesian_to_polar.c                     |  2 +-
 misc/factorial_large_number.c                 | 10 +++---
 numerical_methods/durand_kerner_roots.c       |  6 ++--
 numerical_methods/newton_raphson_root.c       |  2 +-
 numerical_methods/qr_eigen_values.c           |  3 +-
 project_euler/problem_13/sol1.c               |  2 +-
 project_euler/problem_14/sol1.c               |  2 +-
 project_euler/problem_15/sol1.c               |  2 +-
 project_euler/problem_19/sol1.c               | 23 ++++++------
 project_euler/problem_20/sol1.c               | 22 ++++++------
 project_euler/problem_21/sol1.c               |  6 ++--
 project_euler/problem_22/sol1.c               |  4 +--
 project_euler/problem_23/sol1.c               | 12 +++----
 project_euler/problem_23/sol2.c               | 18 +++++-----
 project_euler/problem_25/sol1.c               |  2 +-
 sorting/shell_sort2.c                         |  4 +--
 20 files changed, 92 insertions(+), 94 deletions(-)

diff --git a/data_structures/binary_trees/threaded_binary_trees.c b/data_structures/binary_trees/threaded_binary_trees.c
index b9ff2560..6ef5f728 100644
--- a/data_structures/binary_trees/threaded_binary_trees.c
+++ b/data_structures/binary_trees/threaded_binary_trees.c
@@ -22,7 +22,7 @@
 
 /**
  * Node, the basic data structure of the tree
- **/
+ */
 typedef struct Node
 {
     int data;           /**< stores the number */
@@ -34,7 +34,7 @@ typedef struct Node
  * creates a new node
  * param[in] data value to be inserted
  * \returns a pointer to the new node
- **/
+ */
 node *create_node(int data)
 {
     node *ptr = (node *)malloc(sizeof(node));
diff --git a/machine_learning/adaline_learning.c b/machine_learning/adaline_learning.c
index 341d7de2..bfbdbe9d 100644
--- a/machine_learning/adaline_learning.c
+++ b/machine_learning/adaline_learning.c
@@ -30,17 +30,18 @@
 #include <stdlib.h>
 #include <time.h>
 
-#define MAX_ITER 500  // INT_MAX  ///< Maximum number of iterations to learn
+/** Maximum number of iterations to learn */
+#define MAX_ITER 500  // INT_MAX
 
 /** structure to hold adaline model parameters */
 struct adaline
 {
-    double eta;       ///< learning rate of the algorithm
-    double *weights;  ///< weights of the neural network
-    int num_weights;  ///< number of weights of the neural network
+    double eta;      /**< learning rate of the algorithm */
+    double *weights; /**< weights of the neural network */
+    int num_weights; /**< number of weights of the neural network */
 };
 
-#define ACCURACY 1e-5  ///< convergence accuracy \f$=1\times10^{-5}\f$
+#define ACCURACY 1e-5 /**< convergence accuracy \f$=1\times10^{-5}\f$ */
 
 /**
  * Default constructor
diff --git a/machine_learning/kohonen_som_topology.c b/machine_learning/kohonen_som_topology.c
index 3820d713..4af9c9c8 100644
--- a/machine_learning/kohonen_som_topology.c
+++ b/machine_learning/kohonen_som_topology.c
@@ -28,14 +28,12 @@
 #endif
 
 #ifndef max
-#define max(a, b)                                              \
-    (((a) > (b)) ? (a) : (b)) /**< shorthand for maximum value \
-                               */
+/** shorthand for maximum value */
+#define max(a, b) (((a) > (b)) ? (a) : (b))
 #endif
 #ifndef min
-#define min(a, b)                                              \
-    (((a) < (b)) ? (a) : (b)) /**< shorthand for minimum value \
-                               */
+/** shorthand for minimum value */
+#define min(a, b) (((a) < (b)) ? (a) : (b))
 #endif
 
 /** to store info regarding 3D arrays */
@@ -193,8 +191,8 @@ int save_u_matrix(const char *fname, struct array_3d *W)
  * \param[in] X matrix to search
  * \param[in] N number of points in the vector
  * \param[out] val minimum value found
- * \param[out] idx_x x-index where minimum value was found
- * \param[out] idx_y y-index where minimum value was found
+ * \param[out] x_idx x-index where minimum value was found
+ * \param[out] y_idx y-index where minimum value was found
  */
 void get_min_2d(double **X, int N, double *val, int *x_idx, int *y_idx)
 {
@@ -300,7 +298,6 @@ double update_weights(const double *X, struct array_3d *W, double **D,
  *
  * \param[in] X data set
  * \param[in,out] W weights matrix
- * \param[in] D temporary vector to store distances
  * \param[in] num_samples number of output points
  * \param[in] num_features number of features per input sample
  * \param[in] num_out number of output points
diff --git a/machine_learning/kohonen_som_trace.c b/machine_learning/kohonen_som_trace.c
index 3569f974..68c3bb18 100644
--- a/machine_learning/kohonen_som_trace.c
+++ b/machine_learning/kohonen_som_trace.c
@@ -5,6 +5,7 @@
  *
  * \author [Krishna Vedala](https://github.com/kvedala)
  *
+ * \details
  * This example implements a powerful self organizing map algorithm.
  * The algorithm creates a connected network of weights that closely
  * follows the given data points. This this creates a chain of nodes that
@@ -16,23 +17,22 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
-#ifdef _OPENMP  // check if OpenMP based parallellization is available
+#ifdef _OPENMP  // check if OpenMP based parallelization is available
 #include <omp.h>
 #endif
 
 #ifndef max
-#define max(a, b)                                              \
-    (((a) > (b)) ? (a) : (b)) /**< shorthand for maximum value \
-                               */
+/** shorthand for maximum value */
+#define max(a, b) (((a) > (b)) ? (a) : (b))
 #endif
 #ifndef min
-#define min(a, b)                                              \
-    (((a) < (b)) ? (a) : (b)) /**< shorthand for minimum value \
-                               */
+/** shorthand for minimum value */
+#define min(a, b) (((a) < (b)) ? (a) : (b))
 #endif
 
 /**
- * Helper function to generate a random number in a given interval.
+ * \brief Helper function to generate a random number in a given interval.
+ * \details
  * \n Steps:
  * 1. `r1 = rand() % 100` gets a random number between 0 and 99
  * 2. `r2 = r1 / 100` converts random number to be between 0 and 0.99
@@ -41,22 +41,23 @@
  * y = (b - a) \times \frac{\text{(random number between 0 and RAND_MAX)} \;
  * \text{mod}\; 100}{100} + a \f]
  *
- * \param[in] a lower limit
- * \param[in] b upper limit
+ * \param a lower limit
+ * \param b upper limit
  * \returns random number in the range \f$[a,b)\f$
  */
 double _random(double a, double b)
 {
-    return ((b - a) * (rand() % 100) / 100.f) + a;
+    int r = rand() % 100;
+    return ((b - a) * r / 100.f) + a;
 }
 
 /**
  * Save a given n-dimensional data martix to file.
  *
- * \param[in] fname filename to save in (gets overwriten without confirmation)
- * \param[in] X matrix to save
- * \param[in] num_points rows in the matrix = number of points
- * \param[in] num_features columns in the matrix = dimensions of points
+ * \param [in] fname filename to save in (gets overwriten without confirmation)
+ * \param [in] X matrix to save
+ * \param [in] num_points rows in the matrix = number of points
+ * \param [in] num_features columns in the matrix = dimensions of points
  * \returns 0 if all ok
  * \returns -1 if file creation failed
  */
@@ -89,7 +90,7 @@ int save_nd_data(const char *fname, double **X, int num_points,
 
 /**
  * Get minimum value and index of the value in a vector
- * \param[in] x vector to search
+ * \param[in] X vector to search
  * \param[in] N number of points in the vector
  * \param[out] val minimum value found
  * \param[out] idx index where minimum value was found
@@ -111,7 +112,7 @@ void get_min_1d(double const *X, int N, double *val, int *idx)
 /**
  * Update weights of the SOM using Kohonen algorithm
  *
- * \param[in] X data point
+ * \param[in] x data point
  * \param[in,out] W weights matrix
  * \param[in,out] D temporary vector to store distances
  * \param[in] num_out number of output points
@@ -164,7 +165,6 @@ void update_weights(double const *x, double *const *W, double *D, int num_out,
  *
  * \param[in] X data set
  * \param[in,out] W weights matrix
- * \param[in] D temporary vector to store distances
  * \param[in] num_samples number of output points
  * \param[in] num_features number of features per input sample
  * \param[in] num_out number of output points
diff --git a/misc/cartesian_to_polar.c b/misc/cartesian_to_polar.c
index f7c4f3e2..e7b02128 100644
--- a/misc/cartesian_to_polar.c
+++ b/misc/cartesian_to_polar.c
@@ -6,7 +6,7 @@ const double pi = 3.141592653589793238462643383279502884;
 /**
 give as arguments to the executable two x and y coordinates
 outputs a polar coordinate
-**/
+*/
 int main()
 {
     double x, y;
diff --git a/misc/factorial_large_number.c b/misc/factorial_large_number.c
index 09634c3b..c3939b38 100644
--- a/misc/factorial_large_number.c
+++ b/misc/factorial_large_number.c
@@ -10,7 +10,7 @@
 
 /**
  * dynamically large number
- **/
+ */
 typedef struct _large_num
 {
     char *digits;            /**< array to store individual digits */
@@ -20,7 +20,7 @@ typedef struct _large_num
 /**
  * create a new large number
  * \returns pointer to a large number
- **/
+ */
 large_num *new_number(void)
 {
     large_num *new_num = (large_num *)malloc(sizeof(large_num));
@@ -33,7 +33,7 @@ large_num *new_number(void)
 /**
  * delete all memory allocated for large number
  * \param[in] num pointer to large_num to delete
- **/
+ */
 void delete_number(large_num *num)
 {
     free(num->digits);
@@ -44,7 +44,7 @@ void delete_number(large_num *num)
  * add a digit to the large number
  * \param[in,out] num
  * \param[in] value value of the digit to insert
- **/
+ */
 void add_digit(large_num *num, unsigned int value)
 {
     if (value > 9)
@@ -62,7 +62,7 @@ void add_digit(large_num *num, unsigned int value)
 /**
  * multiply large number with another integer and
  * store the result in the same large number
- **/
+ */
 void multiply(large_num *num, unsigned long n)
 {
     int i;
diff --git a/numerical_methods/durand_kerner_roots.c b/numerical_methods/durand_kerner_roots.c
index 8b032aa7..f29158c4 100644
--- a/numerical_methods/durand_kerner_roots.c
+++ b/numerical_methods/durand_kerner_roots.c
@@ -46,7 +46,7 @@
  * \param[in] degree degree of polynomial
  * \param[in] x point at which to evaluate the polynomial
  * \returns \f$f(x)\f$
- **/
+ */
 long double complex poly_function(double *coeffs, unsigned int degree,
                                   long double complex x)
 {
@@ -91,7 +91,7 @@ char check_termination(long double delta)
 
 /***
  * the comandline inputs are taken as coeffiecients of a polynomial
- **/
+ */
 int main(int argc, char **argv)
 {
     double *coeffs = NULL;
@@ -130,7 +130,7 @@ int main(int argc, char **argv)
 #if defined(DEBUG) || !defined(NDEBUG)
     /**
      * store intermediate values to a CSV file
-     **/
+     */
     FILE *log_file = fopen("durand_kerner.log.csv", "wt");
     if (!log_file)
     {
diff --git a/numerical_methods/newton_raphson_root.c b/numerical_methods/newton_raphson_root.c
index 7f071db9..952b2b49 100644
--- a/numerical_methods/newton_raphson_root.c
+++ b/numerical_methods/newton_raphson_root.c
@@ -4,7 +4,7 @@
  * Newton-Raphson interpolation algorithm.
  *
  * \author [Krishna Vedala](https://github.com/kvedala)
- **/
+ */
 
 #include <complex.h> /* requires minimum of C99 */
 #include <limits.h>
diff --git a/numerical_methods/qr_eigen_values.c b/numerical_methods/qr_eigen_values.c
index 0b0d1bf0..24d643d4 100644
--- a/numerical_methods/qr_eigen_values.c
+++ b/numerical_methods/qr_eigen_values.c
@@ -10,6 +10,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
+
 #include "qr_decompose.h"
 #ifdef _OPENMP
 #include <omp.h>
@@ -95,7 +96,7 @@ double **mat_mul(double **A, double **B, double **OUT, int R1, int C1, int R2,
  * \note The matrix \f$A\f$ gets modified
  *
  * \param[in,out] A matrix to compute eigen values for
- * \param[out] eig_vals resultant vector containing computed eigen values
+ * \param[out] eigen_vals resultant vector containing computed eigen values
  * \param[in] mat_size matrix size
  * \param[in] debug_print 1 to print intermediate Q & R matrices, 0 for not to
  * \returns time for computation in seconds
diff --git a/project_euler/problem_13/sol1.c b/project_euler/problem_13/sol1.c
index e5c1fd90..e55f19d4 100644
--- a/project_euler/problem_13/sol1.c
+++ b/project_euler/problem_13/sol1.c
@@ -40,7 +40,7 @@ int get_number(FILE *fp, char *buffer, uint8_t *out_int)
 /**
  * Function to add arbitraty length decimal integers stored in an array.
  * a + b = c = new b
- **/
+ */
 int add_numbers(uint8_t *a, uint8_t *b, uint8_t N)
 {
     int carry = 0;
diff --git a/project_euler/problem_14/sol1.c b/project_euler/problem_14/sol1.c
index cfb2422f..f999dcbf 100644
--- a/project_euler/problem_14/sol1.c
+++ b/project_euler/problem_14/sol1.c
@@ -23,7 +23,7 @@
 /**
  * Computes the length of collatz sequence for a given
  * starting number
- **/
+ */
 long long collatz(long long start_num)
 {
     long long length = 1;
diff --git a/project_euler/problem_15/sol1.c b/project_euler/problem_15/sol1.c
index c0dd1c79..5cf3184e 100644
--- a/project_euler/problem_15/sol1.c
+++ b/project_euler/problem_15/sol1.c
@@ -13,7 +13,7 @@
  * and N right options, without preference for order.
  * Hence, the path can be be traced in N out of 2N number of ways.
  * This is the same as binomial coeeficient.
- **/
+ */
 unsigned long long number_of_paths(int N)
 {
     unsigned long long path = 1;
diff --git a/project_euler/problem_19/sol1.c b/project_euler/problem_19/sol1.c
index 90ea0f04..f7854d79 100644
--- a/project_euler/problem_19/sol1.c
+++ b/project_euler/problem_19/sol1.c
@@ -10,7 +10,7 @@
  * Month is identified by an integer -\n
  * > 0 = Jan and 11 = December\n
  * For February, adjust for leap year outside the function.
- **/
+ */
 char get_month_days(short month)
 {
     if (month == 1) /* February has 28 days. Adjust leap year in the loop */
@@ -37,7 +37,7 @@ char get_month_days(short month)
 /**
  * return 1 if input year is a leap year
  * otherwise, return 0
- **/
+ */
 char is_leap_year(short year)
 {
     if ((year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0)))
@@ -79,10 +79,10 @@ int main(int argc, char **argv)
     const short start_year = 1901;
     const short end_year = 2000;
 
-    /**
+    /*
      * Let us identify days i.e., Sunday thru Saturday with integers - 0 thru 6
-     *respectively Jan 1 1901 was a Tuesday
-     **/
+     * respectively Jan 1 1901 was a Tuesday
+     */
     char start_day = 2;
 
     for (int year = start_year; year <= end_year; year++)
@@ -90,9 +90,10 @@ int main(int argc, char **argv)
         char is_leap = is_leap_year(year);
         for (char month = 0; month < 12; month++)
         {
-            /**
+            /*
              * These two for-loops count the start of day for the next month.
-             * Hence, we have to skip the last December count */
+             * Hence, we have to skip the last December count
+             */
             if (year == end_year && month == 11)
                 continue;
 
@@ -109,11 +110,11 @@ int main(int argc, char **argv)
             }
 #endif
 
-            /** Main Algorithm:
+            /* Main Algorithm:
              * every week has 7 days hence, the start of next day would be
-             *modulo 7 add to this, the current start date and ensure the result
-             *is still modulo 7!
-             **/
+             * modulo 7 add to this, the current start date and ensure the
+             * result is still modulo 7!
+             */
             start_day = ((days % 7) + start_day) % 7;
 
             /* If start-day is a Sunday, increment counter */
diff --git a/project_euler/problem_20/sol1.c b/project_euler/problem_20/sol1.c
index 1c6e9e1f..a78e014d 100644
--- a/project_euler/problem_20/sol1.c
+++ b/project_euler/problem_20/sol1.c
@@ -3,7 +3,7 @@
  * \brief [Problem 20](https://projecteuler.net/problem=20) solution
  * \author [Krishna Vedala](https://github.com/kvedala)
  *
- * Implementation uses a custom `big_int` structure that can store arbitrarilty
+ * Implementation uses a custom `big_int` structure that can store arbitrarily
  * large integer numbers.
  */
 #include <stdio.h>
@@ -13,12 +13,12 @@
 /**
  * store arbitratily large integer values
  * as a linked list of digits.
- **/
+ */
 typedef struct _big_int
 {
-    char value;                  /** tens place (single digit) */
-    struct _big_int *next_digit; /** hundreds place */
-    struct _big_int *prev_digit; /** units place */
+    char value;                  /**< tens place (single digit) */
+    struct _big_int *next_digit; /**< hundreds place */
+    struct _big_int *prev_digit; /**< units place */
 } big_int;
 
 #ifdef DEBUG
@@ -33,7 +33,7 @@ void print_digit(const big_int *my_int)
 /**
  * Function that allocates memory to add another
  * digit at the MSB
- **/
+ */
 big_int *add_digit(big_int *digit, char value)
 {
     if (digit == NULL)
@@ -72,7 +72,7 @@ big_int *add_digit(big_int *digit, char value)
 /**
  * Function to remove digits preceeding the
  * current digit.
- **/
+ */
 char remove_digits(big_int *digit, int N)
 {
     if (digit == NULL)
@@ -133,10 +133,10 @@ int main(int argc, char **argv)
             ptr->value = tmp;
 
             if (i == N)
-                /**
+                /*
                  * sum digits on the last iteration
                  * this avoid having another loop over all digits
-                 **/
+                 */
                 sum_digits += tmp;
 
             if (ptr->next_digit)
@@ -158,9 +158,9 @@ int main(int argc, char **argv)
     printf("%d! = ", N);
 #endif
 
-    /** Notice that in the loop above, we make sure that at the end of the loop,
+    /* Notice that in the loop above, we make sure that at the end of the loop,
      * ptr is pointing to the last digit. Thus we can avoid using another loop.
-     **/
+     */
     // ptr = &my_int;
     // /* move ptr to the MSB digit */
     // while (ptr->next_digit)
diff --git a/project_euler/problem_21/sol1.c b/project_euler/problem_21/sol1.c
index d5b77145..aac5b453 100644
--- a/project_euler/problem_21/sol1.c
+++ b/project_euler/problem_21/sol1.c
@@ -9,7 +9,7 @@
 
 /**
  * function to return the sum of proper divisors of N
- **/
+ */
 unsigned long sum_of_divisors(unsigned int N)
 {
     unsigned long sum = 1 + N; /* 1 and itself are always a divisor */
@@ -40,12 +40,12 @@ int main(int argc, char **argv)
     if (argc == 2)
         MAX_N = atoi(argv[1]);
 
-    /**<
+    /*
      * We use an array of flags to check if a number at the index was:
      * not-processed = 0
      * is amicable = 1
      * not amicable = -1
-     **/
+     */
     char *flags = (char *)calloc(MAX_N, sizeof(char));
 
     clock_t start_time = clock();
diff --git a/project_euler/problem_22/sol1.c b/project_euler/problem_22/sol1.c
index dbb44d56..f7df5f2d 100644
--- a/project_euler/problem_22/sol1.c
+++ b/project_euler/problem_22/sol1.c
@@ -16,7 +16,7 @@
 
 /**
  * Alphabetical sorting using 'shell sort' algorithm
- **/
+ */
 void shell_sort(char data[][MAX_NAME_LEN], int LEN)
 {
     const int gaps[] = {701, 301, 132, 57, 23, 10, 4, 1};
@@ -44,7 +44,7 @@ void shell_sort(char data[][MAX_NAME_LEN], int LEN)
 
 /**
  * Alphabetical sorting using 'lazy sort' algorithm
- **/
+ */
 void lazy_sort(char data[][MAX_NAME_LEN], int LEN)
 {
     int i, j;
diff --git a/project_euler/problem_23/sol1.c b/project_euler/problem_23/sol1.c
index c2f3d1bc..e469659e 100644
--- a/project_euler/problem_23/sol1.c
+++ b/project_euler/problem_23/sol1.c
@@ -17,7 +17,7 @@ unsigned long MAX_N = 28123; /**< upper limit of numbers to check */
  * -1 if N is deficient
  *  1 if N is abundant
  *  0 if N is perfect
- **/
+ */
 char get_perfect_number(unsigned long N)
 {
     unsigned long sum = 1;
@@ -43,7 +43,7 @@ char get_perfect_number(unsigned long N)
 
 /**
  * Is the given number an abundant number (1) or not (0)
- **/
+ */
 unsigned long is_abundant(unsigned long N)
 {
     return get_perfect_number(N) == 1 ? 1 : 0;
@@ -51,7 +51,7 @@ unsigned long is_abundant(unsigned long N)
 
 /**
  * Find the next abundant number after N and not including N
- **/
+ */
 unsigned long get_next_abundant(unsigned long N)
 {
     unsigned long i;
@@ -65,13 +65,13 @@ unsigned long get_next_abundant(unsigned long N)
  * of two abundant numbers.
  * \returns 1 - if yes
  * \returns 0 - if not
- **/
+ */
 char is_sum_of_abundant(unsigned long N)
 {
-    /** optimized logic:
+    /* optimized logic:
      * i + j = N   where both i and j should be abundant
      * hence we can simply check for j = N - i as we loop through i
-     **/
+     */
     for (unsigned long i = get_next_abundant(1); i <= (N >> 1);
          i = get_next_abundant(i))
         if (is_abundant(N - i))
diff --git a/project_euler/problem_23/sol2.c b/project_euler/problem_23/sol2.c
index a149010d..bc56089a 100644
--- a/project_euler/problem_23/sol2.c
+++ b/project_euler/problem_23/sol2.c
@@ -22,14 +22,14 @@ long MAX_N = 28123; /**< Limit of numbers to check */
  * Using a whole byte to store a binary info would be redundant.
  * We will use each byte to represent 8 numbers by relying on bits.
  * This saves memory required by 1/8
- **/
+ */
 char *abundant_flags = NULL;
 
 /**
  * \returns -1 if N is deficient
  * \returns 1 if N is abundant
  * \returns 0 if N is perfect
- **/
+ */
 char get_perfect_number(unsigned long N)
 {
     unsigned long sum = 1;
@@ -55,7 +55,7 @@ char get_perfect_number(unsigned long N)
 
 /**
  * Is the given number an abundant number (1) or not (0)
- **/
+ */
 char is_abundant(unsigned long N)
 {
     // return abundant_flags[N >> 3] & (1 << N % 8) ? 1 : 0;
@@ -66,7 +66,7 @@ char is_abundant(unsigned long N)
 
 /**
  * Find the next abundant number after N and not including N
- **/
+ */
 unsigned long get_next_abundant(unsigned long N)
 {
     unsigned long i;
@@ -81,13 +81,13 @@ unsigned long get_next_abundant(unsigned long N)
  * of two abundant numbers.
  * \returns 1 - if yes
  * \returns 0 - if not
- **/
+ */
 char is_sum_of_abundant(unsigned long N)
 {
-    /** optimized logic:
+    /* optimized logic:
      * i + j = N   where both i and j should be abundant
      * hence we can simply check for j = N - i as we loop through i
-     **/
+     */
     for (unsigned long i = get_next_abundant(1); i <= (N >> 1);
          i = get_next_abundant(i))
         if (is_abundant(N - i))
@@ -107,9 +107,9 @@ int main(int argc, char **argv)
     if (argc == 2)
         MAX_N = strtoul(argv[1], NULL, 10);
 
-    /** byte array to store flags to identify abundant numbers
+    /* byte array to store flags to identify abundant numbers
      * the flags are identified by bits
-     **/
+     */
     abundant_flags = (char *)calloc(MAX_N >> 3, 1);
     if (!abundant_flags)
     {
diff --git a/project_euler/problem_25/sol1.c b/project_euler/problem_25/sol1.c
index 30bd697b..9c7c2254 100644
--- a/project_euler/problem_25/sol1.c
+++ b/project_euler/problem_25/sol1.c
@@ -15,7 +15,7 @@
 /**
  * Function to add arbitraty length decimal integers stored in an array.\n
  * a + b = c = new b
- **/
+ */
 unsigned int add_numbers(unsigned char *a, unsigned char *b, unsigned char *c,
                          int N)
 {
diff --git a/sorting/shell_sort2.c b/sorting/shell_sort2.c
index bf471592..362a7075 100644
--- a/sorting/shell_sort2.c
+++ b/sorting/shell_sort2.c
@@ -8,8 +8,6 @@
 #include <stdlib.h>
 #include <time.h>
 
-#define ARRAY_LEN(x) (sizeof(x) / sizeof((x)[0]))
-
 /** Helper function to print array values */
 void show_data(int *arr, long len)
 {
@@ -29,7 +27,7 @@ inline void swap(int *a, int *b)
 
 /**
  * Optimized algorithm - takes half the time as other
- **/
+ */
 void shell_sort(int *array, long LEN)
 {
     const int gaps[] = {701, 301, 132, 57, 23, 10, 4, 1};