1.#include <stdio.h>

      #include <string.h>

      main()
      {
          static char str[] = "...ab..cd,,ef.hi";

          printf("|%s|\n", strtok(str, "."));
          printf("|%s|\n", strtok(NULL, ","));
          printf("|%s|\n", strtok(NULL, ",."));
          printf("|%s|\n", strtok(NULL, ",."));
      }

      Running this example program produces the following results:

        $ RUN STRTOK_EXAMPLE1
        |ab|
        |.cd|
        |ef|
        |hi|
        $

    2.#include <stdio.h>

      #include <string.h>

      main()
      {
         char *ptr,
              string[30];

         /* The first character not in the string "-" is "A".  The   */
         /* token ends at "C.                                        */

          strcpy(string, "ABC");
          ptr = strtok(string, "-");
          printf("|%s|\n", ptr);

          /* Returns NULL because no characters not in separator      */
          /* string "-" were found (i.e.  only separator characters   */
          /* were found)                                              */

          strcpy(string, "-");
          ptr = strtok(string, "-");
          if (ptr == NULL)
              printf("ptr is NULL\n");

      }

      Running this example program produces the following results:

        $ RUN STRTOK_EXAMPLE2
        |abc|
        ptr is NULL
        $