使用 fgetc() 時，分配的變量給出 EOF

Question

我正在將一個名為 strings.txt 的文件讀入 c 程序。 我在 Ubuntu 上運行它。 function fgets() 有效，但 fgetc() 總是返回 EOF 而不是 char。 我究竟做錯了什么？

我知道如果達到該點或某處出現錯誤， fgetc 將返回 EOF。 但是錯誤在哪里？

strings.txt 文件包含在下面的第二個文件中。

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

#define MAX 1024

void *num_substring(void *hold);

int total = 0;
int n1,n2;
char *s1,*s2;
FILE *fp;
int at;

int readf(FILE *fp)
{
    char c;
    int words = 1;

    fp=fopen("strings.txt", "r");
    if(fp==NULL){
        printf("ERROR: can't open string.txt!\n");
        return 0;
    }
    else
    {
        s1=(char *)malloc(sizeof(char)*MAX);
        if(s1==NULL){
            printf("ERROR: Out of memory!\n");
            return -1;
        }
        s2=(char *)malloc(sizeof(char)*MAX);
        if(s2==NULL){
            printf("ERROR: Out of memory\n");
            return -1;
        }
        /*read s1 s2 from the file*/
        s1=fgets(s1, MAX, fp);
        s2=fgets(s2, MAX, fp);
        n1=strlen(s1);  /*length of s1*/
        n2=strlen(s2)-1; /*length of s2*/

        //error happens here and the while is never run
        c = fgetc(fp);
        while (c == EOF)
        {
            printf("c != EOF\n");
            if (c == '\n' || c == ' ')
            {
                words++;
                printf("word in loop count = %d\n", words);
            }

            c = fgetc(fp);
        }
...
}

int main(int argc, char *argv[])
{
    int count;

    count = readf(fp);
...
}

字符串.txt

This is an apple. That is a pear. That is an orange. That is a kiwi fruit. This is an avocado. There is a peach on the tree. This is a banana. That is a berry. That is cherry. That is a haw. This is a lemon. There is a hickory on the tree. 
is

Answer 1

您可以調用ferror()來確定是否發生錯誤。

您應該能夠使用從ferror()獲得的值調用perror() ) 以獲取人類可讀的錯誤消息。