asked on

Limiting Input

Hi I need help on limiting input. That is to only allow the user to enter 1 char. I'm doing a program that has a menu, and that i would want to allow the user to only enter 1 digit and nothing more.

Eg.
Choice -> 1 (expected to see only 1 if the users enter "1bc" it still only shows 1 unless the user enter 2* or 3 and so forth.
so we won't see

Choice -> 1a
Choice -> 11
Choice -> bb
etc
Enter is required to proceed which is why i din use getch() after that using isdigit to double check.

Thanks for any help that can be rendered.

Zyloch

Hi jyhiroko,

Might not be the best way, and I'm not sure if C has some function like charAt, but you can use strncpy is one way:

http://www.harpercollege.edu/bus-ss/cis/166/mmckenzi/lect11/l11c.htm

Regards,
Zyloch

Jaime Olivares

You can implement your own input function. Something like

int GetOption()
{
char key;
char option=0;

do {
key = getch();
if (isdigit(key)) {
option = key;
putch(option);
} else if (key==8) { /* backspace */
option = 0;
putch(8);
} else if (key==13) { /* enter */
if (option)
return option;
}
}
}

SOLUTION

Jaime Olivares

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER CERTIFIED SOLUTION

ankuratvb

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ankuratvb

Change this line:
> if(key==13) break;

to

if(key==13 && option!=-1) break;

This will keep asking for a digit even if the user presses enter without entering a digit.