Subj : Re: year 11 maths survey
To   : comp.programming
From : Rob Thorpe
Date : Sun Sep 11 2005 01:07 pm

Jon Harrop wrote:
> Richard Heathfield wrote:
> > I would. A well-written C++ program which takes advantage of common C++
> > idioms is effectively unreadable to anyone who knows C but not C++.
>
> Yes.
>
> >> C programmers can use C++ compilers.
> >
> > Sure, if they want to write C++.
>
> Or if they want to write C. I often compile C using a C++ compiler without
> any trouble.
>
> > COBOL programmers can do the same. But,
> > whilst it is true that some of my C programs will compile under a C++
> > compiler, many do not. And a few that do compile will have different
> > semantics under C++ than they do under C.
>
> Then you're probably overusing trigraphs! ;-)

There are several difference between C and C++, the precedence order is
slightly different for example.  The most common problem is the meaning
of the void pointer which is quite different in C to C++.  If you
write:

x = malloc(sizeof(x_t));

That is considered fine by many C programmers (including me).  It's not
right in C++ and without a cast it will at least cause a warning.
Compile a large C program with a C++ compiler and you get at least a
slew of warning, and normally errors.

.