tp 8.3

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#define NMAX 1001

void checkAlloc(const void *const p) {
  if (p == NULL) {
    perror("");
    exit(EXIT_FAILURE);
  }
}

typedef struct Node {
  char text[NMAX];
  struct Node *prev, *next;
} Node;

Node *newNode(const char s[NMAX]) {
  Node *node = malloc(sizeof(Node));
  checkAlloc(node);
  node->next = node->prev = NULL;
  strcpy(node->text, s);
  return node;
}

typedef struct {
  Node *first, *last;
} List;

void initList(List *list) {
  list->first = list->last = NULL;
}

void printList(const List *const list) {
  for (Node *it = list->first; it; it = it->next) {
    fputs(it->text, stdout);
  }
  fputc('\n', stdout);
}

void freeList(List *list) {
  Node *next;
  for (Node *it = list->first; it; it = next) {
    next = it->next;
    free(it);
  }
}

void addOrd(List *list, const char text[NMAX]) {
  Node *node = newNode(text);
  Node *prev = NULL, *curr = list->first;
  while (curr != NULL && strcmp(curr->text, text) < 0) {
    prev = curr;
    curr = curr->next;
  }
  if (prev == NULL) {//to start
    node->next = list->first;
    list->first = node;
  } else {
    prev->next = node;
    node->next = curr;
  }
}

int main(int argc, char *argv[]) {
  if (argc == 1) {
    fprintf(stderr, "arg error!\n");
    exit(-1);
  }

  List list;
  initList(&list);
  FILE *file = fopen(argv[1], "r");
  if (file == NULL) {
    perror("");
    freeList(&list);
    exit(EXIT_FAILURE);
  }

  static char line[NMAX];
  while (fgets(line, NMAX, file)) {
    addOrd(&list, line);
  }

  printList(&list);
  freeList(&list);
  if (fclose(file) == EOF) {
    perror("");
  }
  return EXIT_SUCCESS;
}