Update ex3.py : add alternate solution without find (not seen in course).

Chapter_3/ex3.py

-
 txt="Les objectifs de Python en font un langage pedagogique ideal.C'est un langage     general-purpose:il s'adapte a toutes les applications"
 
 seperatorList = " ,.;-'\":\n/\\?+()’!°"
@@ -22,3 +21,25 @@ while len(txt) > 0:
         txt=""
 
 print("Il y a {0} mots dans la phrase.".format(n_words))
+
+# solution alternative sans utiliser "find"
+# moins optimale sur de grands textes
+
+in_word = False
+words = []
+curword = ""
+
+for letter in txt:
+    if letter in separators:
+        if in_word:
+            words.append(curword)
+            curword = ""
+            in_word = False
+    else:
+        in_word = True
+        curword += letter
+
+if in_word:
+    words += curword
+
+print("il y a", len(words), "mot(s)")
\ No newline at end of file