def replace_the_last_occurrence_of_a_character_in_a_string(s, char_to_replace, replacement_char):
pos = s.rfind(char_to_replace)
if pos != -1:
s = s[:pos] + replacement_char + s[pos + 1:]
return s
s = "c++ c python c++ java c++ php"
char_to_replace = 'c'
replacement_char = 'W'
s = replace_the_last_occurrence_of_a_character_in_a_string(s, char_to_replace, replacement_char)
print(s)
'''
run:
c++ c python c++ java W++ php
'''