#include <stdio.h>
  #include <string.h>
  #include <stdbool.h>
  #include <stdlib.h>
  
  // Conditionals

  const bool          IS_DEBUG            = true;

  
  // Constants

  const unsigned int  BUFFER_SIZE         = 620;	  // (FIELD SIZE = 20) x (NUMBER OF FIELDS = 31) = 620 BYTES // OPTIMIZATION  
  const unsigned int  FIELD_SIZE          = 20;     // NUMBER OF CHAR PER FIELD

  const char          CSV_DELIMITERS[]    = ",";
  
  // Globals
  char**              CSV_HEADER_FIELDS;
  unsigned int        CSV_NB_FIELDS;
  

  
  //########################################################################

  void display_header()
  {
      for(unsigned int i = 0; i < CSV_NB_FIELDS; i++)
      {
          printf("%d - %s\n", i, CSV_HEADER_FIELDS[i]);
      }
  }
  

  
  //########################################################################

  void read_csv_header(char * header_line)
  {
      int     line_length = strlen(header_line);
      int     nb_fields   = 0;
      char*   string_ptr  = header_line;
  
      // Count the occurrences of delimiters
      while (NULL != string_ptr)
      {
          nb_fields++;
          string_ptr = strpbrk(string_ptr, CSV_DELIMITERS);
          if (NULL != string_ptr)
          {
              string_ptr++;
          }
      }
  
      // Globals allocation

      if (IS_DEBUG) printf("number of fields: %d\n",nb_fields); // TO BE REMOVED LATER 

      CSV_NB_FIELDS       = nb_fields;
      CSV_HEADER_FIELDS   = malloc( nb_fields * sizeof(char*) );
  
      char* token         = strtok(header_line, CSV_DELIMITERS);                  // strtok init.
  
      // Re-read the line to get the header of the columns
      for (unsigned int i = 0; i < nb_fields; i++)
      {
          CSV_HEADER_FIELDS[i] = malloc( FIELD_SIZE * sizeof(char) );             // alloc
          memset(CSV_HEADER_FIELDS[i], 0, FIELD_SIZE);                            // 0 init.
          strcpy(CSV_HEADER_FIELDS[i], token);                                    // copy field in the structure
          token = strtok(NULL, CSV_DELIMITERS);                                   // loop to get a new field label
      }
  
      if (IS_DEBUG) display_header();
  }
  

  //########################################################################

  void read_csv_file(const char * filename)
  {
      FILE*   fp = fopen(filename, "r");
      char    buffer[BUFFER_SIZE];
  
      // Check if the file is really opened
      if (NULL == fp)
      {
          fprintf(stderr, "Unable to open file: %s\n", filename);
          return;
      }
  
      // 1st row is a header with field descriptions
      fgets(buffer, BUFFER_SIZE, fp);
      read_csv_header(buffer);
  
      // Remaining rows are the entries
      while ( NULL != fgets(buffer, BUFFER_SIZE, fp) )
      {
          char*           token;
          unsigned int    i = 0;
  
          // strtok init.
          token = strtok(buffer, CSV_DELIMITERS);
  
          while (NULL != token)
          {

              if (IS_DEBUG) printf("Field %d is %s\n", i++, token);
  
              // ...
              // you can strcpy the `token` string in your data structures
              // ...
  

              token = strtok(NULL, CSV_DELIMITERS);
          }
      }
  
      fclose(fp);
  }
  

  //########################################################################

  void usage(const char * prog_name)
  {
      printf("Usage is %s your_csv_file\n\n", prog_name);
  }
  

  //########################################################################

  int main(int argc, char * argv[])
  {
      if (2 != argc)
      {
          usage(argv[0]);
          return 0;
      }
  
      read_csv_file(argv[1]);
      for(unsigned int i = 0; i < CSV_NB_FIELDS; i++)
      {
          free(CSV_HEADER_FIELDS[i]);
      }
      free(CSV_HEADER_FIELDS);
  
      return 0;

  }