From: "A. Sinan Unur" <asu1 AT c-o-r-n-e-l-l DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: HELP with CONIO.H
Date: 25 Feb 2003 15:20:04 GMT
Organization: Cornell University
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"helen" <lab_darzo AT libero DOT it> wrote in 
news:6a5a8fa116bf7cfe3195a3dd08958be4 DOT 113557 AT mygate DOT mailgate DOT org:

> I have DJGPP working fine even with allegro.
> it's on win98.
> 
> I run this and a blank screen goes. why ? (see below)
> ---
> /*    parabola non centrata nell'origine */
> 
> #include <stdio.h>
> #include <math.h>
> #include <conio.h>
> 
> int main()
> {
> int h,w;
>   clrscr();

this clears the screen.

>      h=300;
>      w=200;
>         gotoxy(120,350);

this is definitely out of bounds for text mode (80x25).

>         textcolor(4);
>         printf("il testo è in 120,350\n");

you shouldn't mix stdio functions with conio functions. so, you should 
have used cprintf here. however, since you set the output coordinates to 
somewhere beyond the textmode screen, that would have probably crashed 
your program.

>         getchar();
> 
>    // ORA DISEGNO LA FINESTRA...
>    textbackground(4);
>       window(10, 20, 10+w, 20+h);

again, this window spans an area larger than the text mode screen.

>          getchar();
>    return 0;
> }
> 
>  I suppose conio.h is not linked or the RHIDE is not well configured.
> any help ???

header files are not linked, they are #include'd. I think the conio 
functions are in the DJGPP libc, so they would be linked automatically. 
The answer is simple, the screen is cleared because you called clrscr().

It is probably not a good idea to try to draw a parabola in text mode.

Sinan.

-- 
A. Sinan Unur
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