SAS/C Library Reference, Vol. 1

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