isupper -- Uppercase Alphabetic Character Test


SYNOPSIS
#include <ctype.h>
int isupper(int c);
DESCRIPTION
isupper
tests an integer value c
to determine whether it is an
uppercase alphabetic character.
RETURN VALUE
isupper
returns 0 if the character is not an uppercase alphabetic
character, or a nonzero value if it is. If the argument is EOF
, 0
is returned.
CAUTION
The effect of isupper
on a noncharacter argument other than EOF
is undefined. The definition of an uppercase character is
locale dependent. Do not assume that isupper
returns either 0 or 1.
EXAMPLE
#include <ctype.h>
#include <stdio.h>
#define MAXLEN 40
main()
{
char id[MAXLEN +1];
char *text;
char input[MAXLEN +1];
int i;
printf("Enter a string (maximum of %d characters):n", MAXLEN);
text = gets(input);
/* Copy uppercase "identifier" from text to id. */
for (i = 0; i < 40 && isupper(text[i]); ++i)
id[i] = text[i];
id[i] = '0';
/* Only initial uppercase characters get copied. */
printf("%sn", id);
}
RELATED FUNCTIONS
isalpha
, islower
, tolower
, toupper
SEE ALSO