DaniWeb Forum Index > Software Development > C

Turbo C help

Please support our C advertiser: Programming Forums - DaniWeb Sister Site

•

Join Date: Sep 2006

Posts: 327

Reputation: Colin Mac is on a distinguished road

Solved Threads: 22

Colin Mac

Offline

Posting Whiz

Turbo C help

Sep 21st, 2006

Hi, I'm a beginner and just started Turbo C

I wrote this program in the editor

main()
{
float years, days;
printf ("Please type your age in years:");
scanf ( "%f", &years);
days = years * 365;
printf ("You are%.1f days old.\n", days);
}

I then run the program and it asks me my age in years. I input my age and when I press enter to tell me my age in days it goes from the DOS window back to the turbo C editor, i then press Alt+ F5 to go back to the DOS screen and it then tells me my age in days

So the program is working but my question is-

Why does it jump back to the turbo c window when I press enter to enter my age? Is this wrong?

Thanks.

•

Join Date: Aug 2005

Posts: 15,511

Reputation: Ancient Dragon has a reputation beyond repute

Solved Threads: 1480

Ancient Dragon Ancient Dragon is offline

Offline

Still Learning

Re: Turbo C help

Sep 21st, 2006

>>Why does it jump back to the turbo c window when I press enter to enter my age? Is this wrong?

because you didn't tell the program to do anything else. If you want it to wait so that you can see what's on the screen, put a getch() at the end so that it will wait for keybord input.

After calling scanf() with an integer, the scanf() function does not remove the <Enter> key from the keyboard buffer. You must flush the input buffer or else the program won't wait for the next getch() .

Help with Code Tags

(Toggle Plain Text)

int main()
{
    float years, days;
    printf ("Please type your age in years:");
    scanf ( "%f", &years);
   getchar(); // remove '\n' from keyboard buffer
    days = years * 365;
    printf ("You are%.1f days old.\n", days);
   getchar();
   return 0;
}

Last edited by Ancient Dragon; Sep 21st, 2006 at 8:43 pm.

•

Join Date: Jun 2006

Posts: 7,629

Reputation: ~s.o.s~ has much to be proud of

Solved Threads: 468

~s.o.s~

Offline

Failure as a human

Re: Turbo C help

Sep 22nd, 2006

Better than using scanf which is a pretty complicated function which leaves the input stream dirty try out the alternative functions fgets along with atoi to take the input from user. For the function prototypes look here:
http://www.cplusplus.com

And why are you using the age old Turbo Compiler? If you can, try to install a better IDE as well as a compiler.

The list of all the new compilers and free IDE can be found in the sticky at the top of the C++ forum in "Starting C".

Hope it helped, bye.

I don't accept change; I don't deserve to live.

•

Join Date: Sep 2006

Posts: 327

Reputation: Colin Mac is on a distinguished road

Solved Threads: 22

Colin Mac

Offline

Posting Whiz

Re: Turbo C help

Sep 22nd, 2006

Thanks, I'm using turbo C because that's what we are going to use in college.

I asked my lecturer today and he told me because the getche() function was missing like you said which I had forgotten about so I rewrote it like below
and it worked the way I wanted it to.

main()
{
float years, days;
printf ("Please type your age in years:");
scanf ( "%f", &years);
days = years * 365;
printf ("You are%.1f days old.\n", days);
getche();
}

I'm not fully sure what those extras that you added are for, haven't came across them yet so I'm not going to worry too much for now.. .

Thanks for all your help.

Last edited by Colin Mac; Sep 22nd, 2006 at 2:30 pm.

•

Join Date: Jun 2006

Posts: 7,629

Reputation: ~s.o.s~ has much to be proud of

Solved Threads: 468

~s.o.s~

Offline

Failure as a human

Re: Turbo C help

Sep 22nd, 2006

Well here is the general techinique used to avoid the pitfalls of scanf.
Take a look at this code iif you are really interested in learing something new.

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <stdlib.h>
 
 
int main (void)
{
    char buffer [BUFSIZ] ;
    float years, days;
    printf ("Please type your age in years: ");
    fgets (buffer, BUFSIZ, stdin) ;
    if ( buffer [strlen (buffer)] == '\n')
        buffer [strlen(buffer)] = '\0' ;
    years = atof (buffer) ;
    days = years * 365;
    printf ("\nYou are %.0f days old.\n", days);
    getchar () ;
 
    return 0 ;
}
#include <stdio.h>
#include <stdlib.h>


int main (void)
{
    char buffer [BUFSIZ] ;
    float years, days;
    printf ("Please type your age in years: ");
    fgets (buffer, BUFSIZ, stdin) ;
    if ( buffer [strlen (buffer)] == '\n')
        buffer [strlen(buffer)] = '\0' ;
    years = atof (buffer) ;
    days = years * 365;
    printf ("\nYou are %.0f days old.\n", days);
    getchar () ;

    return 0 ;
}