RE: [Dev-C++] A simple problem

[Ioannis V. <no...@ho...>]

> -----Original Message-----
> From: Ioannis Vranos [mailto:no...@ho...] 
> Sent: Tuesday, November 19, 2002 10:21 PM
> To: 'dev...@li...'
> Subject: RE: [Dev-C++] A simple problem
> 
> 
> > -----Original Message-----
> > From: dev...@li... 
> > [mailto:dev...@li...] On Behalf 
> > Of Paul Ardeleanu
> > Sent: Tuesday, November 19, 2002 1:47 PM
> > To: dev...@li...
> > Subject: [Dev-C++] A simple problem
> > 
> > 
> > Can Anyone tell me why this code WORKS FINE in DevC++? 
> > ANSI C says that it any Ansi compiler should give you an 
> > error (see K&R
> > book).
> > Thank you very much!
> > Paul
> > 
> > -----------------------------------------------------------
> > main ()
> > {
> >   printf("hello, world
> >   \n
> >   
> >   
> >   ");
> >   system("PAUSE");	
> > }
> 
> 
> It is valid C90 code (and not C99).
> 
> The main() thing is implicit int. In C90 you could do:
> 
> 
> const x=7;
> 
> and it was equivallent to const int x=7;
> 
> 
> main() was equivallent to int main(). This is not the case in C99.
> 
> 
> Now both in C90 and C99 if you do not declare a function and 
> you use it, a declaration of the type
> 
> 
> int whatever_you_use(); is assumed. The empty parenthesis is 
> not equivallent to (void) as in C++. Empty parenthesis means 
> that you want to skip argument checking.
> 
> 
> So when you use printf() without <stdio.h>, int printf(); is assumed.


I hadn't checked the entire code. The "broken" string literal is not
guaranteed to be portable (but GCC digests it). Also in your C90 code
you have to return 0; from main(), else you have "undefined behaviour".
K&R2 doesn't return 0; from main() which was the main murmur of C
programmers. Also the castings to malloc() are not needed (=better to be
avoided ) in C, although are used in K&R 2. K&R 2 casts malloc() because
they used a prototype C++ compiler to test the code (as you can read
somewhere in the preface).



Ioannis Vranos
 
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