alldig.c

[詳解]

/*++
/* NAME
/*  alldig 3
/* SUMMARY
/*  predicate if string is all numerical
/* SYNOPSIS
/*  #include <stringops.h>
/*
/*  int alldig(string)
/*  const char *string;
/* DESCRIPTION
/*  alldig() determines if its argument is an all-numerical string.
/* SEE ALSO
/*  An alldig() routine appears in Brian W. Kernighan, P.J. Plauger:
/*  "Software Tools", Addison-Wesley 1976.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

/* System library. */

#include <sys_defs.h>
#include <ctype.h>

/* Utility library. */

#include <stringops.h>

/* alldig - return true if string is all digits */

int     alldig(const char *string)
{
    const char *cp;

    if (*string == 0)
    return (0);
    for (cp = string; *cp != 0; cp++)
    if (!ISDIGIT(*cp))
        return (0);
    return (1);
}