S02 Answer

/* Puzzle S02 -- detect upper case characters */

#include <stdio.h>
#include <stdlib.h>
/* Puzzle S02 -- detect white case characters */

int isWhitespace( int ch )
{
  return ( ch == 0x20 || ch>= 0x09 && ch<= 0x0D ) ;
}

int main(int argc, char *argv[])
{
  char trials[] = {'a', 'B', ' ', '+', 'z', 0x33, 0x09, 0x0A, 0x0B, 0x0C, 0x0D };
  int j, ch;

  for ( j=0; j<sizeof(trials); j++ )
  {
    ch = (int)trials[j] ; /* char in low order byte */
    printf("%02X ", ch );
    if ( isWhitespace( ch ) )
      printf("is whitespace\n");
    else
      printf("is NOT whitespace\n");
  }

  system("PAUSE");
  return 0;
}

Comments:

(1) The whitespace characters consist of space 0x20 and the range of characters 0x09 .. 0x0D. There are minor variations in what different C libraries count as whitespace, so be cautious.

(2) The testing program uses the format code "%02X" to print out the characters to show their ascii code with two digits of hexadecimal.

(3) The array is now an array of char. sizeof(trials) gives the number of bytes, which is now also the number of cells.