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  #1  
Old September 24th, 2002, 07:16 PM
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i have a question about one of the exercises in the k & r book....

hey,

i have a question for someone who has the book, "THE C PROGRAMMING LANGUAGE [2nd Edition]".......

on page 17 and exercise 1-6 it says, "Verify that the expression getchar() != EOF is 0 or 1."

what does this mean? how would i do this?

thanks a lot,

-sean
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Old September 24th, 2002, 07:33 PM
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Basically in C, a comparision evaluates to 0 (false) or 1 (true). An if statement like this:
if (getchar() != EOF) {
...
}
will cause the compiler to evaluate the comparision expression as a 1 (true) or a 0 (false). You could actually assign the result of the comparision to another variable, if you like, something like this:
Code:
int foo;

if (foo = (getchar() != EOF)) {
  /* Do something */
}
printf("%d\n", foo);


the value of foo will be 0 or 1 depending on whether the getchar() returned an end-of-file character or not.

Hope this helps!

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Old September 26th, 2002, 08:00 PM
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Curious - when would getchar() EVER return EOF? Or, is that what it returns when you hit enter?

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Old September 27th, 2002, 03:08 AM
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Nope, the enter key is not the EOF char on any OS that I'm aware of. On *NIX, the EOF character is ^D and on DOS, EOF is ^Z.

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