c - 我在 C 语言中读取 .txt 文件中的单词时遇到一些问题

Question

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

#define WORD_LENGHT 30

typedef struct numnode
{
    char* dataPtr;
    struct numnode* next;

} NUMNODE;

typedef struct num
{
   NUMNODE* head;

} NUM;
//////
//////
//////
int main()
{
    char *wp;
    char word[80];
    int total=0;
    FILE *test= fopen("book.txt", "r");
    while (fscanf (test, "%s",word) == 1)
    {
        //printf("%s\n",word);  //counting how many words in a book.txt
        total++;
    }

    if (total==0)
    {
        printf("File not found\n"); //if no word, then return
        return;
    }

    NUM* dic;
    dic=(NUM*)malloc(sizeof(NUM)*total);
    NUMNODE* temp;
    temp=dic->head;

    FILE*file = fopen("book.txt", "r");
    while(!feof(file))
    {
        wp=malloc(100);  
        printf("test1\n");
        fscanf(file,"%s",wp);
        strcpy(temp->dataPtr,wp);  //strcpy is the error part 
        printf("test2\n");
        temp=temp->next;
    }
    return;
}

this c code read word by word from book.txt and put them to linked list. i got some issues with !feof(file) part.Couldnt figure out what to do.i think strcpy in this loop is the reason of this issue.im waiting for your helps :3

Answer 1

错误是因为结构体成员dataPtr是一个指针，而不是一个数组。所以 strcpy 调用

strcpy(temp->dataPtr,wp);

是错误的，因为它访问非法内存，调用未定义的行为。你需要的是

typedef struct numnode
{
    char dataPtr[100];  // dataPtr changed to an array type
    struct numnode* next;

} NUMNODE;

请注意，dataPtr 必须至少为 wp 指向的缓冲区的大小。