On Fri, 20 Jul 2001, Robert E. Griffith wrote:

> One thing to keep in mind is that C has a few notation short cuts that make
> things less consistant.
>
> Char buffer[20];
>
> This one statement does several things.
>
> 1) it sets aside 20 bytes (each char is 1 byte) of memory.
> 2) it declares a char* named 'buffer'
> 3) it sets the value of the char* buffer to the beginning of the memory it
> set aside.
>
> Number 2 is the confusing part. It does not look like you are declaring a
> pointer, but in most respects buffer behaves as if it was declared "char*
> buffer"

        2 and 3 are false, if you think of `buffer' as a pointer (because
it isn't).

        Actually, `buffer' behaves perfectly consistently if you think of
it as a constant which happens to have type (char *), just as 1 is a
constant that happens to have type (int).  The value of the constant
`buffer' is the address of the start of the array you declared.

> The next confusing thing; Variables of type char* are assumed to point to a
> memory location that has 0 or more byte values that correspond to ASCII
> characters (65 means 'A' and is OK, 200 means nothing in ASCII and is not
> OK) and ending in the value 0 (NULL).  The 0 lets functions know how long
> the string is.

        Actually, this is false, if you mean that the C compiler assumes
this.  It is a convention applied by some library functions.  (I should
say that I'm talking about `real' C compilers;  there are probably some
brain-damaged ones that make this kind of assumption.)

> The C compiler sets aside memory for string literals (like "dog") with one
> extra byte that it sets to 0 (NULL).

        This is true.


        John.

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