I like using it when I'm filling an array with an indeterminate number of elements. I've used this pattern a few times:

    foo foos[255];
    int ct = 0;

    if (<condition for adding first element>)
        foos[ct++] = foo1;

    if (<condition for adding second element>)
        foos[ct++] = foo2;

    ...

    for (int i = 0; i < ct; i++) {
        /* do something with foos[i] */
    }

IMHO, this is more concise and readable than separating the increment and assignment into two lines.

I think users of for/while loops will disagree. Don't forget that =, += , ... can all be abused in the same way.

    (int i=0;i<10;i++)

would count as three lines for purposes of that rule, and the

    i++

as one. I could have been more precise, but I thought it would be understood.

The point is, to be on the safe side, don't use ++/-- in any line (in the sense of ;{}-delimited statement) that is also doing something else.

>Don't forget that =, += , ... can all be abused in the same way.

I didn't, and people should use the same safeguards around them, i.e. don't mix them within lines that do other things, "cleverness" or "C golf" be damned.