#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define DEBUG
#if defined(DEBUG)
#include "xmalloc.h"
#else
#define xmalloc(x, y) malloc(x)
#define xfree(x, y) free(x)
#define xrealloc(x, y, z) realloc(x, y)
#define xmallocdump()
#endif
/* for xmalloc.c */
#define ID_GETLINE 1004
#define ID_NODE    1005
#define ID_WORD    1006

struct node {
  char *data;
  struct node *left, *right;
};

void *push(struct node **root, void *data, int (*cmp)(void *, void *)) {
  struct node *p;
  int c;
  if (!*root) {
    if ((p = xmalloc(sizeof(struct node), ID_NODE)) == 0) {
      fprintf(stderr, "cannot allocate enough memory(struct node), aborted\n");
      exit(-1);
    }
    p->data = data;
    p->left = p->right = 0;
    *root = p;
    return data;
  } 
  if ((c = (*cmp)(data, (*root)->data)) != 0) {
    if ((*cmp)(data, (*root)->data) < 0) {
      return push(&((*root)->left), data, cmp);
    } else {
      return push(&((*root)->right), data, cmp);
    }
  } else {
    return (*root)->data;
  }
}

void *pop(struct node **root) {
  struct node *p;
  void *data;
  if (*root == 0) {
    return 0;
  }
  if ((*root)->left) {
    data = pop(&((*root)->left));
    return data;
  }
  p = *root;
  data = p->data;
  *root = p->right;
  xfree(p, ID_NODE);
  return data;
}

void release(struct node **root, void (*f)(void *)) {
  if (*root != 0) {
    release(&((*root)->left), f);
    release(&((*root)->right), f);
    f((*root)->data);
    xfree(*root, ID_NODE);
    *root = 0;
  }
}

void *mostleft(struct node *root) {
  if (root == 0)
    return 0;
  if (root->left == 0)
    return root->data;
  else
    return mostleft(root->left);
}

void *mostright(struct node *root) {
  if (root == 0)
    return 0;
  if (root->right == 0)
    return root->data;
  else
    return mostright(root->right);
}

#define BUFFSIZE 3 /* >= 2 */
char *mygetline(FILE *fp) {
  static char inbuff[BUFFSIZE];
  char *outbuff_malloc, *tmpbuff;
  char *p, *r;
  int fEOL;

  if ((outbuff_malloc = xmalloc(1, ID_GETLINE)) == NULL) {
    return NULL;
  }
  *outbuff_malloc = '\0';
  fEOL = 0;
  do {
    r = fgets(inbuff, BUFFSIZE, fp);
    if (r == NULL)
      break;
    for (p = inbuff; *p != '\0'; p++)
      ;
    if (*(p - 1) == '\n')
      fEOL = 1;
    if ((tmpbuff = xrealloc(outbuff_malloc, strlen(outbuff_malloc) + strlen(inbuff) + 1, ID_GETLINE)) == NULL) {
      xfree(outbuff_malloc, ID_GETLINE);
      return NULL;
    }
    strcat(tmpbuff, inbuff);
    outbuff_malloc = tmpbuff;
  } while (!fEOL);
  if (strlen(outbuff_malloc) > 0) {
    for (p = outbuff_malloc; *p != '\0'; p++)
      ;
    if (*(p - 1) == '\n')
      *(p - 1) = '\0';
    return outbuff_malloc;
  }
  xfree(outbuff_malloc, ID_GETLINE);
  return NULL;
}

int isSep(char *p) { return (*p == ' ' || *p == '\t' || *p == '\n'); }

char *cutToken(char *p, char **s) {
  char *t, *q;
  int flag;
  if (p == 0)
    return 0;
  flag = 0;
  for (q = p; isSep(q) && *q != '\0'; q++)
    ;
  if (*q == '\0')
    return 0;
  t = q;
  q++;
  for (; !isSep(q) && *q != '\0'; q++)
    ;
  if (*q == '\0')
    flag = 1;
  *q = '\0';
  if (flag)
    *s = 0;
  else
    *s = q + 1;
  return t;
}

void reg(char *s) {
  char *p;
  for (p = s; *p != 0; p++)
    if (isalpha(0xff & *p) && *p >= 'A' && *p <= 'Z')
      *p = *p - 'A' + 'a';
}

struct word {
  int n;
  char w[1];
};

void release_word(struct word *p) {
  xfree(p, ID_WORD);
}

int cmp1(struct word *p, struct word *q) { return strcmp(p->w, q->w); }
int cmp2(struct word *p, struct word *q) { return strlen(p->w) - strlen(q->w); }

int main() {
#define N 1024
  static char filename[N];
  FILE *fp;
  char *p, *q, *r;
  struct word *t, *s;
  struct node *dic = 0;
  struct node *dic2 = 0;

  printf("filename: "); fgets(filename, N, stdin);
  for (p = filename; *p != '\0'; p++)
    ;
  --p;
  while (*p == '\n' || *p == '\r')
    --p;
  p++;
  *p = '\0';
  if ((fp = fopen(filename, "r")) == 0) {
    fprintf(stderr, "cannot open the file: %s aborted.\n", filename);
    exit(1);
  }
  while ((p = mygetline(fp)) != 0) {
    q = p;
    while ((r = cutToken(q, &q)) != 0) {
      if ((t = xmalloc(sizeof(struct word) + strlen(r), ID_WORD)) != 0) {
        strcpy(t->w, r);
        reg(t->w);
        t->n = 1;
        if ((s = push(&dic, t, (int (*)(void *, void *))cmp1)) != t) {
          s->n++;
          xfree(t, ID_WORD);
        }
      }
    }
    xfree(p, ID_GETLINE);
  }
  fclose(fp);
  t = mostleft(dic);  printf("the first word: %s\n", t->w);
  t = mostright(dic);  printf("the last word: %s\n", t->w);

  while ((t = pop(&dic)) != 0)
    if ((s = push(&dic2, t, (int (*)(void *, void *))cmp2)) != t) {
      xfree(t, ID_WORD);
    }
  t = mostright(dic2);  printf("the longest word: %s\n", t->w);
  release(&dic, (void (*)(void *))release_word);
  release(&dic2, (void (*)(void *))release_word);
  xmallocdump();
  return 0;
}

/* end */

Line 20: error: xmalloc.h: No such file or directory
In function 'push':
Line 29: warning: assignment makes pointer from integer without a cast
In function 'mygetline':
Line 101: warning: assignment makes pointer from integer without a cast
Line 114: warning: assignment makes pointer from integer without a cast
In function 'main':
Line 201: warning: assignment makes pointer from integer without a cast