This documentation is copyright © 1998-2001 Sandro Sigala <sandro@sigala.it>.
All rights reserved.
Released under the GNU General Public License.
isdigit
Prototype
#include <ctype.h>
int isdigit(int c);
Description
Returns a true value if the c
character is a decimal-digit character.
Example
#include <ctype.h>
/*
* Return a true value if the argument string is a regular
* decimal number.
*/
int is_number(const char *s)
{
const char *sp;
for (sp = s; *sp != '\0'; ++sp)
if (!isdigit(*sp))
return 0;
return sp > s;
}
References
ISO C 9899:1990 7.3.1.4