我是否設置了我的文件指針錯誤？

Question

#include "stdafx.h" 
#include "string.h" 
#include "stdio.h" 
void CharReadWrite(FILE *fin); 
FILE *fptr2; 

int _tmain(int argc, _TCHAR* argv[]) 
{ 

    char filename[]="ReadMe.txt"; 
    if (fopen_s(&fptr2, filename, "r") != 0) 
     printf("File stream %s was not opened\n", filename); 
    else 
     printf("The file %s was opened\n", filename); 
    CharReadWrite(fptr2); 
    fclose(fptr2); 
    return 0; 
    } 
void CharReadWrite(FILE *fin){ 
    int c; 
    while ((c=fgetc(fin)) !=EOF) { 
     putchar(c);} 
} 

Answer 1

你打開readme.txt文件獲得寫作：

fopen_s(&fptr2, filename, "w") 

但隨後將它傳遞給CharReadWrite：

CharReadWrite(fptr2); 

它試圖從中讀取數據：

c=fgetc(fin) 

你的意思是打開它來閱讀，通過"r"到fopen_s？

如果打開ReadMe.txt失敗，您也繼續並調用CharReadWrite。

Answer 2

一個問題是，即使您未能打開它，您也正在嘗試從（然後關閉）fptr2中讀取數據。

嘗試：

#include "stdafx.h" 
#include "string.h" 
#include "stdio.h" 
void CharReadWrite(FILE *fin); 
FILE *fptr2; 

int _tmain(int argc, _TCHAR* argv[]) 
{ 

    char filename[]="ReadMe.txt"; 
    if (fopen_s(&fptr2, filename, "w") != 0) 
    { 
     printf("File stream %s was not opened\n", filename); 
    } 
    else 
    { 
     printf("The file %s was opened\n", filename); 
     CharReadWrite(fptr2); 
     fclose(fptr2); 
    } 
    return 0; 
} 

Answer 3

的問題是這一行：

如果（fopen_s（& fptr2，文件名， 「W」）！= 0）

當您通過「W 'flag，"Create an empty file for writing. If a file with the same name already exists its content is erased and the file is treated as a new empty file."

而是使用「r +」標誌。

Answer 4

您正在打開寫入文件並嘗試從中讀取文件（fgetc）...