Thread: Help: Find a integer digit in a string

Hi.
I need to know if the very first character each line of a .TXT file is a int (from 0 to 9)?
In the following code i think the program give me the first character, but how do I know if it is a integer?

Code:

 
sscanf(file, "%d, &x);
  if (file[0] == "%*[^0-9]%d")
     {
	printf("%d\n", x);
     }

Thanks in advance.

You could use the isalpha() C function.

i.e.

Code:

if( !isalpha(...) )

I think isalpha() is for C++. I'm working on C.
But thanks anyway.

Originally Posted by Vivasso

I think isalpha() is for C++. I'm working on C.
But thanks anyway.

Nope it's C. #include <ctype.h>

Yes you are right is for C. But doesn't help me because it checks if it is a alphanumeric character, or not.... A character like "#" it's not alphanumeric, and it's not what I want. I need to know only if it it belongs to [0,9].

Try the isdigit() function then... same include file.

Do I need to use atoi function?
[code]
if isdigit (file[0] =0)
than....
[\code]
it's enough?

I think it's working....I will be back to confirm.

OK Thank's it works.
Case close!