Amy Cash - Pipes - String Manipulation Practice Exercises

string_manipulation.rb

@@ -1,30 +1,110 @@
 # A method to reverse a string in place.
 def string_reverse(my_string)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  j = my_string.length - 1
+  reversed_string = my_string
+  while i < (my_string.length  / 2)
+    temp = reversed_string[i]
+    reversed_string[i] = reversed_string[j]
+    reversed_string[j] = temp
+    i += 1
+    j -= 1
+  end
+  return reversed_string
 end
 
-# A method to reverse each word in a sentence, in place.
 def reverse_words(my_words)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  start = 0
+  segment = ""
+
+  #check for space at start
+  until my_words[i] != " "
+    i += 1
+    start += 1
+  end
+
+  while i < my_words.length
+    if my_words[i] == " "
+      my_words[start..(i-1)] = string_reverse(segment)
+      segment = ""
+      start = i + 1
+    else
+      segment << my_words[i]
+    end #if statement
+    i += 1
+  end #while statement
+  my_words[start..(i-1)] = string_reverse(segment)
+  return my_words
 end
 
+
+# sentence = "Yoda  is   awesome"
+# puts "Original: #{sentence}"
+# reversed_sentence = "awesome   is  Yoda"
 # A method to reverse the words in a sentence, in place.
 def reverse_sentence(my_sentence)
-  puts "NOT IMPLEMENTED"
+  string_reverse(my_sentence)
+  return reverse_words(my_sentence)
 end
 
 # A method to check if the input string is a palindrome.
 # Return true if the string is a palindrome. Return false otherwise.
 def palindrome_check(my_phrase)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  j = my_phrase.length - 1
+
+  until i >= j
+    if my_phrase[i] == " "
+      i += 1
+    elsif my_phrase[j] == " "
+      j -= 1
+    end #first if statement
+
+    if my_phrase[i] == my_phrase[j]
+      i += 1
+      j -= 1
+    else
+      return false
+    end #second if statement
+  end  #until
   return true
-end
+end #method
+
 
 # A method that updates the string by replacing consecutive repeating characters
 # with a number representing the frequncy. The replacement is done only if the
 # string length will get reduced by the process.
+
 def encode_repeating(my_string)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  j = 0
+
+  until i == my_string.length
+
+    letter_count = 1
+
+    until my_string[j] != my_string[j + 1]
+      letter_count += 1
+      j += 1
+    end #end until
+
+    if letter_count > 2
+      my_string[i + 1] = (letter_count).to_s
+      my_string.slice!((i + 2)..(i + (letter_count - 1)))
+      i += 2
+      j = i
+    elsif letter_count == 2
+      i += 2
+      j = i
+    else
+      i += 1
+      j = i
+    end
+
+  end #end until
+
+  return my_string
 end
 
 ### ---- END OF METHODS
@@ -50,6 +130,7 @@ def encode_repeating(my_string)
   puts "BUG! The reversed words should be '#{reversed_words}' and not '#{my_words}'"
 end
 
+
 puts "Test 3: reversed sentence"
 sentence = "Yoda  is   awesome"
 puts "Original: #{sentence}"
@@ -66,28 +147,28 @@ def encode_repeating(my_string)
 puts "BUG: madam is a palindrome and should return true" if palindrome_check(phrase) != true
 phrase = "empty"
 puts "BUG: empty is not a palindrome and should return false" if palindrome_check(phrase) != false
-# optional challenge
-# phrase = "nurses run"
-# puts "BUG: 'nurses run' is a palindrome and should return true" if palindrome_check(phrase) != true
+puts "optional challenge"
+phrase = "nurses run"
+puts "BUG: 'nurses run' is a palindrome and should return true" if palindrome_check(phrase) != true
 puts "Palindrome test complete."
 
 # Optional Question #5
-# puts "Test 5: Encode test"
-# test1 = "aaabbbbbcccc"
-# encode_repeating(test1)
-# if test1 != "a3b5c4"
-#   puts "BUG! 'aaabbbbbcccc' should get encoded to 'a3b5c4', not '#{test1}'"
-# end
-#
-# test2 = "xxxyttttgeee"
-# encode_repeating(test2)
-# if test2 != "x3yt4ge3"
-#   puts "BUG! 'xxxyttttgeee' should get encoded to 'x3yt4ge3', not '#{test2}'"
-# end
-#
-# test3 = "ddbbfffgjjjj"
-# encode_repeating(test3)
-# if test3 != "ddbbf3gj4"
-#   puts "BUG! 'ddbbfffgjjjj' should get encoded to 'ddbbf3gj4', not '#{test3}'"
-# end
-# puts "Encode test complete."
+puts "Test 5: Encode test"
+test1 = "aaabbbbbcccc"
+encode_repeating(test1)
+if test1 != "a3b5c4"
+  puts "BUG! 'aaabbbbbcccc' should get encoded to 'a3b5c4', not '#{test1}'"
+end
+
+test2 = "xxxyttttgeee"
+encode_repeating(test2)
+if test2 != "x3yt4ge3"
+  puts "BUG! 'xxxyttttgeee' should get encoded to 'x3yt4ge3', not '#{test2}'"
+end
+
+test3 = "ddbbfffgjjjj"
+encode_repeating(test3)
+if test3 != "ddbbf3gj4"
+  puts "BUG! 'ddbbfffgjjjj' should get encoded to 'ddbbf3gj4', not '#{test3}'"
+end
+puts "Encode test complete."