#include <stdio.h>
#include <ctype.h>

main()
{
int val, test = 2;

val = isdigit(test);
printf("%i \n", test);

if (val != 0) puts("is a digit");
else puts("is not a digit");

return 0;
}


Output :
2
is not a digit

Whats wrong ?

noobi schrieb...
> #include <stdio.h>
> #include <ctype.h>
> 
> main()
> {
> int val, test = 2;
> 
> val = isdigit(test);
> printf("%i \n", test);
> 
> if (val != 0) puts("is a digit");
> else puts("is not a digit");
> 
> return 0;
> }
> 
> 
> Output :
> 2
> is not a digit
> 
> Whats wrong ?

isXXX Functions work for chars (or the integer number of a char). You have assigned the integer 2 to test. Interpreted as a char it's a control char (below the space character in the ASCII table). To assign the ASCII 2 character to test write the assignment as

   test = '2'; /* ASCII 2 == decimal 50 */

- Heinz

Big thanks for your help.

In article <MPG.197c7537d2409aa39896c9@news.digitalmars.com>, Heinz Saathoff says...
>
>noobi schrieb...
>> #include <stdio.h>
>> #include <ctype.h>
>> 
>> main()
>> {
>> int val, test = 2;
>> 
>> val = isdigit(test);
>> printf("%i \n", test);
>> 
>> if (val != 0) puts("is a digit");
>> else puts("is not a digit");
>> 
>> return 0;
>> }
>> 
>> 
>> Output :
>> 2
>> is not a digit
>> 
>> Whats wrong ?
>
>isXXX Functions work for chars (or the integer number of a char). You have assigned the integer 2 to test. Interpreted as a char it's a control char (below the space character in the ASCII table). To assign the ASCII 2 character to test write the assignment as
>
>   test = '2'; /* ASCII 2 == decimal 50 */
>
>- Heinz