#  StringReverse.py   (c) Kari Laitinen

#  http://www.naturalprogramming.com

#  2006-03-02  File created.
#  2022-12-16  Converted to Python 3.

#  String literals can be written both with single quotes
#  and with double quotes.

#  Python does not have type char, but single-character
#  strings can be considered characters.

print( "\n This program is able to reverse a string." \
      "\n Please, type in a string.\n\n   ", end="" )

string_from_keyboard  =  input()

print( "\n String length is %d." % len( string_from_keyboard ) )

print( "\n\n String in reverse character order: \n   ", end="" )

character_index  =  len( string_from_keyboard )


while character_index  >  0 :

   character_index  =  character_index  -  1
   print(  string_from_keyboard[ character_index ], end=" " )

#  The following loop uses special string indexing techniques of
#  Python. The index of last character is -1, the index of
#  penultimate character is -2, etc.

print( "\n\n Again in reverse character order: \n   " , end="" )

character_index  =  0

while character_index  >  - len( string_from_keyboard ) :

   character_index  =  character_index  -  1
   print(  string_from_keyboard[ character_index ], end=" " )


#  In order to show the reversed string without spaces, one 
#  possibility is to do the following:

character_index  =  len( string_from_keyboard )

reversed_string  =  ""

while character_index  >  0 :

   character_index  =  character_index  -  1
   reversed_string  +=  string_from_keyboard[ character_index ]
   
print( "\n\n Reversed without spaces: \n   "  +  reversed_string, end="" )


#  Yet another possibility is to convert the string to a list of characters,
#  reverse the list, and then convert the list to a string:

given_string_as_list  =  list( string_from_keyboard )
given_string_as_list.reverse()
reversed_string  =  "".join( given_string_as_list )

print( "\n\n Reversed as list: \n   "  +   reversed_string )