C Programming on the IBM PC (C Programmers Reference Guide Series)

2017-07-07 02:10:07

isdigit

#include <ctype.h>int isdigit(int ch);

The isdigit( ) function returns nonzero if ch is a digit—that is, 0 through 9. Otherwise, zero is returned.

Related functions are isalnum( ), isalpha( ), iscntrl( ), isgraph( ), isprint( ), ispunct( ), and isspace( ).