Question

我尝试创建struct typedef movie_t并将其添加到列表中。它包含标题，导演，评级和年份。我的代码只输出标题。我不明白为什么它没有输出movie_t结构的所有成员？

例如，我已定义：

movie_t *first_movie = {"The Outsiders","Francis Ford Coppola",'PG13',1983}

但是当我运行我的程序时，它只输出标题：

list[0] = The Outsiders
list[1] = The Outsiders
list[2] = The Outsiders
list[3] = The Outsiders
list[4] = The Outsiders
list[5] = The Outsiders
list[6] = The Outsiders
list[7] = The Outsiders
list[8] = The Outsiders
list[9] = The Outsiders

basiclist.h

#ifndef BASICLIST_H_
#define BASICLIST_H_

typedef struct node {
  void * data;         /* pointer to data */
  struct node * next;  /* pointer to next next node */
} node_t;

int list_add(node_t ** list, void * data);

#endif

movie.h

#ifndef MOVIE_H
#define MOVIE_H
#define SIZE_LIMIT 25
#define RATING_SIZE 5

typedef enum {G, PG, PG13, R} rating_t;

typedef struct {
    char rating;
    char title[SIZE_LIMIT];
    char director[SIZE_LIMIT];
    int year;
}movie_t;


void get_movie(movie_t * movie);
void print_movie(const movie_t * movie);

#endif /* MOVIE_H */

的main.c

#include "movie.h"
#include <stdlib.h>
#include <stdio.h>
#include "basiclist.h"

int list_add(node_t ** list, void * data) {
  int ret = 0;
  node_t * newnode = (node_t *) malloc(sizeof(node_t));
  if (newnode == NULL) {
    ret = -1;
  }
  else {
    newnode->data = data;
    newnode->next = *list;
  }
  *list = newnode;
  return ret;
}

int main (void)
{
  int ii;
  movie_t * new_movie;
  movie_t *first_movie = {"The Outsiders","Francis Ford Coppola",'PG13',1983};
  node_t * list = NULL;
  node_t * curr;

  for(ii=0;ii<10;ii++) {
    new_movie = (movie_t *) malloc(sizeof(int));
    *new_movie = *first_movie;
    list_add(&list, new_movie);
  }

  ii = 0;
  curr = list;
  while (curr != NULL) {
    printf("list[%d] = %s\n", ii, *((movie_t *) curr->data));
    ii++;
    curr = curr->next;
  }
  printf("It worked!\n");
  return 0;
}

Answer 1

printf("list[%d] = %s\n", ii, *((movie_t *) curr->data));：movie_t和movie_t*不合适%s。您为move_t*制作自定义打印功能（ print_movie ）。

之类的东西

void print_movie(FILE* fp, const movie_t *m){
    static const char *raiting[] = { "G", "PG", "PG13", "R"};
    fprintf(fp, "%s\t%s\t%s\t%d\n", m->title, m->director, raiting[m->rating], m->year);
}

将原型void print_movie(const movie_t * movie);更改为void print_movie(FILE* fp, const movie_t *m);
或者更改print_movie的姓名和电话。

at main

更改printf("list[%d] = %s\n", ii, *((movie_t *) curr->data));
到print_movie(stdout, curr->data);

另外
改变movie_t *first_movie = {"The Outsiders","Francis Ford Coppola",'PG13',1983};
到movie_t first_movie = {"The Outsiders","Francis Ford Coppola", (char)PG13, 1983};

和

更改

typedef struct {
    char rating;
    char title[SIZE_LIMIT];
    char director[SIZE_LIMIT];
    int year;
}movie_t;

到

typedef struct {
    char title[SIZE_LIMIT];
    char director[SIZE_LIMIT];
    char rating;//or rating_t rating;
    int year;
}movie_t;

和

for(ii=0;ii<10;ii++) {
  new_movie = (movie_t *) malloc(sizeof(int));//int !!
  *new_movie = *first_movie;
  list_add(&list, new_movie);
}

到

for(ii=0;ii<10;ii++) {
  new_movie = malloc(sizeof(*new_movie));
  *new_movie = first_movie;
  list_add(&list, new_movie);
}

将结构添加到列表并获得正确的输出

1 个答案: