thanks for "down" answers

[Guy Harris]

>Severeal respondents have pointed out that many compilers would NOT accept
>			(char_var = getchar()) != EOF
>because getchar() returns an integer, EOF may be a negative integer, and
>on many compilers char variables may not accept signed integers.

Well, actually, most compilers will accept it, which is the problem -
it'll pass the compiler without complaint, but *still* not work on
machines where "char" is unsigned.  And, frankly, it may not work on
machines where "char" is signed, either; the problem is that
"getchar()", on a machine with 8-bit bytes, can return either

	1) a value in the range 0 to 255, which represents a character
	   read from the standard input

or

	2) EOF, usually -1, which represents an end-of-file condition.

The intent is that EOF not be a value in the range 0 to 255 (some
implementation may give it such a value, but that merely means the
implementor didn't know what they were doing).

On a machine with unsigned "char"s, and 8-bit bytes, a "char" can have a
value in the range 0 to 255.  If EOF is -1, assigning EOF to a "char"
on a 2's complement machine gives the value 255, which does not compare
equal to EOF (-1).

On a machine with signed "char"s, and 8-bit bytes, a "char" can have a
value in the range -128 to 127.  If EOF is -1, assigning EOF to a "char"
gives the value -1 - but then, on a 2's complement machine, so does
assigning the value 255.  This means that if you read a character from
the file with the hex value 0xFF - which is "y with a diaresis" in ISO
Latin #1, so even in a pure text file you can have such a character - it
will look just like an EOF.

>I have entirely missed that point.  This is how I was shown and taught.

Oh dear.  Sounds like the person who taught you needs a little remedial
education; could you please point out to them that assigning the result
of "getchar()" to a "char" variable is incorrect?

>I have directly asked a couple of the especially kind respondents on
>their way of handling this.  If you have an unusual excellent
>suggestion I would be most glad to read about it.

There's only one valid suggestion, and that's to have the variable to
which the value of "getchar()" is assigned be of some signed integral
type larger than "char"; "int" is the best choice ("short" might work on
some implementations, possibly most implementations, but it's wisest not
to fool Mother Nature; "long" will work, but it's overkill and may be
inefficient).