文件处理中的EOF标记问题 [英] EOF Marker Problem in Files Handling

问题描述

在我的下面的代码中，我展示了fseek& ftell函数。

说我输入ABCD然后输入EOF !!

输出应为4;相反它显示6.

此外，EOF不会被接受与ABCD在同一行（行）中，如果我移动到下一行，它只被接受。



例如。

说，

我输入，

ABCDE

EOF

它应该将字符数读为5.但它正在读为7.

5 + 1（下一行） = 6

但是编译器返回7作为结果。



//无法理解为什么!!

//如果你能告诉我为什么EOF与INPUT（在这种情况下是ABCDE）在同一行中被接受，我真的很感激。



****************************** *



<前郎=cs> / * 使用ftell& fseek * /

#include< stdio.h>
#include< conio.h>

int main（）
{
FILE * fp;
long n;
char c;

fp = fopen（ RANDOM， w）;

while （（c = getchar（））！= EOF）
putc（c，fp）;

printf（ 输入字符数=％ld，ftell（ FP））;

fclose（fp）;

fp = fopen（ RANDOM， r）;

n = 0L;

while （feof（fp）== 0 ）
{
fseek（fp，n， 0 ）; / * 第（n + 1）个字符的位置* /
printf（ \ n％c的位置是％ld，getc（fp），ftell（fp））;
n = n + 5L;
}

putchar（' \ n'）;

fseek（fp，-1L， 2 ）; / * 最后一个角色的位置* /

do
{
putchar（getc（fp））;
}
while （fseek（fp，-2L， 1 ））;

fclose（fp）;

return 0 ;
}

解决方案

如果按字符串末尾的ENTER键，系统将添加 \\ n （回车和换行）。并且EOF始终是键盘输入的单独行，因为只有在自己输入时才能识别。

In my following code I am demonstrating the fseek & the ftell functions.
Say I input ABCD and then the EOF !!
The output should be 4; instead it is showing 6.
Moreover the EOF is NOT being accepted in the same line(row) as ABCD, it is ONLY being accepted if I move to the next line(s).

For eg.
Say,
I input,
ABCDE
"EOF"
It should read the number of characters as 5. But it is reading it as 7.
5 + 1(for the next line) = 6
But the compiler is returning 7 as the result.

// Unable to Understand Why !!
// Also I would really appreciate if you could tell me why the EOF is not being accepted in the same line as the INPUT(in this case ABCDE).

******************************

/* WAP that uses ftell & fseek */

#include<stdio.h>
#include<conio.h>

int main()
{
    FILE *fp;
    long n;
    char c;

    fp=fopen("RANDOM","w");

    while((c=getchar())!=EOF)
        putc(c,fp);

    printf("No of Characters Entered = %ld",ftell(fp));

    fclose(fp);

    fp=fopen("RANDOM","r");

    n=0L;

    while(feof(fp)==0)
    {
        fseek(fp,n,0);          /* Position to (n+1)th character */
        printf("\nPosition of %c is %ld",getc(fp),ftell(fp));
        n=n+5L;
    }

    putchar('\n');

    fseek(fp,-1L,2);            /* Position to the Last Character */

    do
    {
        putchar(getc(fp));
    }
    while(fseek(fp,-2L,1));

    fclose(fp);

return 0;
}

解决方案

If you press the ENTER key at the end of your string then the system will add \r\n (Carriage return and Line feed). And the EOF is always a separate line on input from the keyboard, as it is only recognised when entered on its own.

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