> ./main cat nap dog
Given input:
 cat
 .
Expected output:
 Looking for 3 words
 Result:
 cat:1
 nap:0
 dog:0

#define LENGTH(s) (sizeof(s) / sizeof(*s))

/* Structures */
typedef struct {
  char *word;
  int counter;
} WordCountEntry;


int process_stream(WordCountEntry entries[], int entry_count)
{
  short line_count = 0;
  char buffer[30];

  while (fgets(buffer,sizeof(buffer),stdin)) {
    if (*buffer == '.')
      break;
    /* Compare against each entry */
    int i = 0;
    while (i < entry_count) {
      if (!strcmp(entries[i].word, buffer))
        entries[i].counter++;
      i++;
    }
    line_count++;
  }
  return line_count;
}


void print_result(WordCountEntry entries[], int entry_count)
{
  fprintf(stdout,"Result:n");

 for(int i=0; i <=entry_count;i++){
   printf("%s:%dn", entries[i].word, entries[i].counter);
 }
}


void printHelp(const char *name)
{
  fprintf(stderr,"usage: %s [-h] <word1> ... <wordN>n", name);
}


int main(int argc, char **argv)
{
  const char *prog_name = *argv;

  WordCountEntry entries[argc];
  int entryCount = 0;

  while ((*argv) != NULL) {
    if (**argv == '-') {

      switch ((*argv)[1]) {
        case 'h':
          printHelp(prog_name);
      break;
        case'f':
          freopen((*argv)[2],"w",stdout);
          break;
        default:
          fprintf(stderr,"%s: Invalid option %s. Use -h for help.n",
                 prog_name, *argv);
      }
    } else {
      if (entryCount < argc-1) {
        entries[entryCount].word = *argv;
        entries[entryCount++].counter = 0;

      }
    }
    argv++;
  }
  if (entryCount == 0) {
    fprintf(stderr,"%s: Please supply at least one word. Use -h for help.n",
           prog_name);
    return EXIT_FAILURE;
  }
  if (entryCount == 1) {
    fprintf(stdout,"Looking for a single wordn");
  } else {
    fprintf(stdout,"Looking for %d wordsn", entryCount);
  }
  process_stream(entries, entryCount);
  print_result(entries, entryCount);

  return EXIT_SUCCESS;
}