Question

我知道你可以关闭一个文件，但我想尝试使用倒带功能，但我得到了一个奇怪的错误。首先，我读取一个文件并计算单词数，然后我尝试快退（只是为了练习文件处理），并输出以下错误：看起来问题是最后一行代码。

以下是代码：

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

int readFile(FILE  *f, char *fileName) {
    int count = 0;
    char ch;

    f = fopen(fileName, "r");
    if ( f == NULL ) {
        printf("Cannot open %s file, please verify it's in the right location\n", fileName);
    }

    while ( (ch = fgetc(f) ) != EOF ) {
        if ( ch == '\n' ) {
            count++;
        }

    }
    printf("The count number is %d", count);
    return count;

}


int main() {

FILE *wordInput = NULL;
    int i, j, k = 0;
    char c;
    char *point; // pointer that points to a word
    char **dictionary; // pointer that points to variable point
    int count = 0;
    int dictChoice; // which dictionary are they picking
    int numLetters = 4; // number of letters for each word

    FILE *fPoint = NULL;


    char *name = "smallDictionary.txt";

    readFile(wordInput, name);

    rewind(wordInput);


    return 0;
}

Answer 1

int readFile(FILE *f, char *fileName)

由于您尝试修改FILE指针，因此需要将指针传递给指向FILE或FILE **的指针。将功能标题更改为

int readFile(FILE **f, char *fileName)

在调用者中，您需要将指针传递给FILE *对象：

FILE *pf;
int n = readFile(&pf, "filename.txt");

此外，当您完成操作文件后，立即致电fclose

fclose(pf);

重绕文件指针

1 个答案: