Beginner post-increment question

[Stang1]

The following statement:

line_buf[line_len++] = ' ';
is equivalent to:

line_buf[line_len] = ' ';
line_len++;

because post-increments are done AFTER the non-incremented values are
used in the statement.
Correct?

[DiAvOl]

yes, it's correct but note that you should avoid to:

1) use the increment or decrement operators on a variable that appears
more than once in an expression

For example avoid using constructs like the following

n = 1;
y = n++ + n++;

2) use the increment or decrement operators on a variable that is part
of more than one argument of a function

Example to avoid

printf("%d %d\n", number, number*number++);

The reason is because the second argument might be evaluated before
the first one

[borkhuis]

DiAvOl wrote:

yes, it's correct but note that you should avoid to:

1) use the increment or decrement operators on a variable that appears
more than once in an expression

For example avoid using constructs like the following

n = 1;
y = n++ + n++;

2) use the increment or decrement operators on a variable that is part
of more than one argument of a function

Example to avoid

printf("%d %d\n", number, number*number++);

The reason is because the second argument might be evaluated before
the first one

You forgot the one thing to avoid:

3) Never use pre or post increment as parameters to macros, as a macro
might use the parameter more than once. As a consequence, item 2
should be "never use increment or decrement on parameters to a
function", as you might not know if this is a real function, or that
this was implemented as a macro.

Kind regards,
Johan Borkhuis

[CBFalconer]

Flash Gordon wrote:

>

.... snip ...

>
implementation is *not* free to feed your mother to the
ravenous bug blatter beast of traal.

Ahh. That explains many of my problems. :-)

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

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