How to stimulate EOF without preceding newline in C

Question

Lets say I have the below C code:

int getLine (char line[])
{
    int c, i=0;
    while( (c=getchar()) != EOF )
           line[i++]=c;
    line[i++] = c;
    return i;
}

>> Enter: 007
>> ^Z
>> Output:

If we closely observe the way I give output above, I am pressing Enter before stimulating EOF. This means, the length of string is 4 not 3 (excluding EOF).

When I am doing my exercises, I am really facing some trouble with that extra \n.

How do I stimulate EOF without newline? Is it possible at all?

>> Enter: 007^Z
>> ^Z
>> Output: length=6

On which platform? On Unix and derivatives, you would type the EOF 'character' twice — usually control-D rather than control-Z, though. That may also work on Windows; I don't know, but it is worth a try. (On Unix, control-D makes the data on the line available to the program. The first control-D gives it what you've typed already; the second gives it zero bytes to read, which is the indication of EOF.) — Jonathan Leffler, Jan 07 '13 at 16:02
You should not save `EOF` in a `char` since `EOF` is negative and `char` could be `unsigned`. — effeffe, Jan 07 '13 at 16:06
on my shell Linux its working `~$ ./try 07070707:~$ ` as commented by Mr. Jonathan Leffler — Grijesh Chauhan, Jan 07 '13 at 16:11
`EOF` is not a character, it's a condition. Imagine you ask your daughter for a banana and she says: "There are no bananas". The sentence "There are no bananas" is not a banana. — pmg, Jan 07 '13 at 16:17

score 2 · Accepted Answer · answered Jan 07 '13 at 16:14

2

Converting my comment into an answer:

On which platform? On Unix and derivatives, you would type the EOF 'character' twice — usually control-D rather than control-Z, though. That may also work on Windows; I don't know, but it is worth a try.

(A response comment affirms that the platform is Windows.)

On Unix, control-D makes the data on the line available to the program. The first control-D gives it what you've typed already; the second gives it zero bytes to read, which is the indication of EOF.

answered Jan 07 '13 at 16:14

Jonathan Leffler

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Any references about it? I indeed find it that two `^d` can work like Enter in terminal and make me so puzzled. – Tony Aug 21 '14 at 03:58
I've not formally verified that they cover it, but I'd expect Stevens (et al) [Advanced Programming in the Unix Environment](http://www.amazon.com/Programming-Environment-Addison-Wesley-Professional-Computing/dp/0321637739/) or Rochkind [Advanced Unix Programming](http://www.amazon.com/Advanced-UNIX-Programming-Marc-Rochkind/dp/0131411543/) to cover it, and so might other Unix or Linux programming books, usually in the chapter on terminal handling. – Jonathan Leffler Aug 21 '14 at 05:46

unwind · Answer 2 · 2013-01-07T16:14:16.110

Then avoid storing the newline, in the loop. It's not as if you're being forced to store all characters regardless of value. :)

Also, you're not terminating the string correctly. This:

line[i++] = c;

should be:

line[i] = '\0';

And of course, it's sensitive to buffer overflow.

In general, you'd be better of using fgets().

EDIT: I might be missing the point, but it seems to be that the entire focus on EOF is ... misguided, if all you want to do is read a line. Lines are not generally terminated with EOF, but with \n. So the function should probably just store characters until either EOF or \n is encountered.

How to stimulate EOF without preceding newline in C

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