Re: [avr-gcc-list] OT Generic C question

[Julius Luukko]

On Tuesday 20 September 2005 13:41, Trampas wrote:
> I was helping a friend debug some code, he is new to C,  using the Keil
> version of GCC for ARM. Anyway I found the following:
>
> int i;
>
> i=0;
> i=i++;
> //i was still zero that
>
> That is i=i++ never incremented i, now I would have thought the line would
> be the same as:
>
> i=i;
> i=i+1;
>
> So you guys are the smartest people I know when it comes to C so I thought
> I would ask you guys if this is a compiler bug or is my understanding of C
> just been shaken.

++ is a post increment operation. So what happens is that first the value of i 
is assigned to i, then the value of that operation (i=i, which is zero in 
this case) is incremented. But the result is not assigned to anything. The 
correct way is of course

i=0;
i++;

-- 
Julius