#  Uplow.py (c) Kari Laitinen

#  http://www.naturalprogramming.com

#  2006-04-19  File created.
#  2022-12-27  Converted to Python 3.

#  This program demonstrates, among other things, the use of bit operator &.

#  With built-in function ord() it is possible to find out the integer
#  character code of the character in a single-character string.

#  With built-in function chr() it is possible to convert an 
#  integer code to a single-character (unicode) string.


def  convert_string_uppercase( given_string ) :

   character_index  =  0 

   modified_string  =  ""

   while  character_index  <  len( given_string ) :

      if  given_string[ character_index ]  >=  "a" and \
          given_string[ character_index ]  <=  "z" :

         modified_string  +=  \
             chr( ord( given_string[ character_index ] )  &  0xDF )

      else :
      
         modified_string  +=  given_string[ character_index ]

      character_index  +=  1

   return  modified_string


#  The main program.


test_string  =  "Guido van Rossum invented Python." ;

print( "\n String before conversion:  "  +  test_string, end="" )

uppercase_string  =  convert_string_uppercase( test_string )

print( "\n String after conversion:   "  +  uppercase_string, end="" )

print( "\n Better conversion:         "  +  test_string.upper() )