Question

我有一个旨在管理txt文件中学生记录的程序。我试图删除学生记录。程序打开文件，读取内容并打印出来供用户查看。然后，用户输入要删除的行的整数。然后它返回新内容供用户查看。

int deleteStudent()
{
    FILE *dOldFile, *dNewFile;//Original file and New temp file
    char ch;
    int deleteLine, temp = 1;

    dOldFile = fopen(fName, "r");//fName is name of file user enters in previous function
    ch = getc(dOldFile);
while (ch != EOF)
{
    printf("%c", ch);//Prints content of Original file for user to see
    ch = getc(dOldFile);
}
rewind(dOldFile);
printf(" \n Enter line number of the line to be deleted:\n>");
scanf("%d", &deleteLine);//user selects which line of file to be removed


dNewFile = fopen("copy.c", "w");
ch = getc(dOldFile);
while (ch != EOF)
{
    ch = getc(dOldFile);
    if (ch == '\n')
        temp++;
        if (temp != deleteLine) //except the line to be deleted
        {
            putc(ch, dNewFile); //copy all lines in file copy.c
        }
}
fclose(dOldFile);
fclose(dNewFile);
remove(fName);
rename("copy.c", fName);
printf("\n Student Records Remaining:\n");
dOldFile = fopen(fName, "r");
ch = getc(dOldFile);
while (ch != EOF)
{
    printf("%c", ch);
    ch = getc(dOldFile);
}
fclose(dOldFile);
printf("\n");
return 0;
}

问题是，我相信这可能是我的while循环的一个问题，是从 fprintf 打印到新的和重命名的文本文件的内容删除了第一个字符，从我的内容理解，在编辑结束时打印的EOF符号。例如，原始文件有

23 John Smith 18 5555555
  24 Tom Costa 15 5555555
  25 Barry West 35 5555555
  26 Daren carr 22 5555555

例如，如果用户决定删除第3行。这是txt文件中的结果

3 John Smith 18 5555555
  24 Tom Costa 15 5555555
  26 Daren carr225555555ÿ

Answer 1

每件事都很好。只需用while循环替换while循环并删除

 ch = getc(dOldFile);

之前如图所示：

dNewFile = fopen("copy.c", "w");
//ch = getc(dOldFile);    comment this out
while((ch = getc(dOldFile))!=EOF)
  {       
   if (ch == '\n')
    temp++;
    if (temp != deleteLine) //except the line to be deleted
    {
        putc(ch, dNewFile); //copy all lines in file copy.c
    }
   }   //modify while to make it better
  fclose(dOldFile);
  fclose(dNewFile);

ÿ在txt文件中打印为EOF

1 个答案: