我不知道如何将输入文件中的字符串(单词)读取到链表中

Question

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

struct node
{
  char *data;
  struct node *next;
};

void insertNode(struct node**, char *);
void printList(struct node*);

int main()
{
  struct node *head = NULL;
  FILE *fptr;
  char file_name[20];
  char str[1000];
  int numOfChar;

  printf("Enter the name of the file: ");
  scanf("%s",file_name);

  printf("Enter the number of characters per line: ");
  scanf("%d",&numOfChar);

  fptr=fopen(file_name,"r");
    char tokens[100];
  while(fgets(str, sizeof(str), fptr) != NULL)
  {
    while (sscanf(str, "%s", tokens) != EOF)
    {
    }

  }

  fclose(fptr);
  printList(head);

  return 0;
}

void insertNode(struct node** nodeHead, char *data)
{
    struct node* new_node = (struct node*) malloc(sizeof(struct node));
    struct node *last = *nodeHead;
    char *str;

    str= (char *)malloc(60*sizeof(char));
    strcpy(str, data);

    new_node->data  = str;
    new_node->next = NULL;

    if (*nodeHead == NULL)
    {
       *nodeHead = new_node;
       return;
    }

    while (last->next != NULL)
    {
        last = last->next;
    }

    last->next = new_node;
}

我的程序应该将每个单词读入链表，但我无法弄清楚如何从输入文件中获取每个单词/字符串。输入文件是 ASCII 文本文件。有什么建议吗？感谢您的帮助。

void printList(struct node* node)
{
    while(node != NULL)
    {
        printf(" %s ", node->data);
        node = node->next;
    }
}

Answer 1

例如，

您可以使用非常低级别的字符扫描，如以下示例所示 - 它可以扩展到实际接受多个分隔符、分隔符重复等：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main() {
  FILE *fptr;
  char buf[100];
  char *p, *s;
  strcpy(buf, "this is just a test");
  fptr=fopen("test.txt","r");
  while(fgets(buf, sizeof(buf), fptr) != NULL)
  {
    printf("LINE: %sn", buf);
    /* scan characters and print tokens - single space is a separator */
    p = s = buf;
    while(*p!=0) {
      if (*p==' ') {
        *p = 0;
        printf("TOKEN: %sn", s);
        s = p+1;
      }
      p++;
    }
    printf("TOKEN: %sn", s);
  }

  fclose(fptr);
  return 0;
}

调用可能如下所示：

$ cat test.txt
this is test1
this is test2
$ gcc tokens.c && ./a.out
LINE: this is test1
TOKEN: this
TOKEN: is
TOKEN: test1
LINE: this is test2
TOKEN: this
TOKEN: is
TOKEN: test2

Answer 2

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

struct node
{
  char *data;
  struct node *next;
};

void insertNode(struct node**, char *);
void printList(struct node*);

int main()
{
  struct node *head = NULL;
  FILE *fptr;
  char file_name[20];
  char str[1000];
  int numOfChar;

  printf("Enter the name of the file: ");
  scanf("%s",file_name);

  printf("Enter the number of characters per line: ");
  scanf("%d",&numOfChar);

  fptr=fopen(file_name,"r");
  while(fscanf(fptr, "%s ", str) != EOF)
  {
      insertNode(&head, str);
  }

  fclose(fptr);
  printList(head);

  return 0;
}

void insertNode(struct node** nodeHead, char *data)
{
    struct node* new_node = malloc(sizeof *new_node);
    new_node->data = strdup(data);
    new_node->next = NULL;
    while (*nodeHead)
        nodeHead = &(*nodeHead)->next;
    *nodeHead = new_node;
}
void printList(struct node* node)
{
    while(node != NULL)
    {
        printf(" %s ", node->data);
        node = node->next;
    }
}