while loop keeps repeating itself

Question

I've code:

int c;
while((c = getchar()) != EOF)
    putchar(c);

As I know EOF is equal to -1 I read -1 from keyboard(input stream) and it must stop itself,but loop keeps repeating. why?

If you mean you're typing the two characters `-1` then it won't stop (the characters will just be echoed. EOF is signalled by the end of the file: either `Ctrl-Z` (Windows) or `Ctrl-D` (Unix). — TripeHound, Jun 24 '15 at 16:27
Note that in a Windows console, the `Ctrl-Z` will only be recognised as `EOF` when it immediately follows a `newline`, otherwise it is treated as value `26`. — Weather Vane, Jun 24 '15 at 16:50

score 2 · Answer 1 · answered Jun 24 '15 at 16:27

2

-1 is actually two separate characters - and 1 which is not equivalent to EOF. Use Ctrl + d on Linux or Ctrl + z on Windows.

answered Jun 24 '15 at 16:27

haccks

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score 2 · Answer 2 · answered Jun 24 '15 at 16:27

As @SouravKanta alludes to: your loop is reading individual characters one at a time, so if you enter -1, it reads the - and then the 1, neither of which indicates EOF. I believe Cntl-d is what you want, at least in *nix (you don't specify the platform).

while loop keeps repeating itself

2 Answers2