Lauren Cardella -- Carets

string_manipulation.rb

@@ -1,30 +1,148 @@
+require 'pry'
+
 # A method to reverse a string in place.
 def string_reverse(my_string)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  j = my_string.length - 1
+
+  while i < j
+    temp = my_string[i]
+    my_string[i] = my_string[j]
+    my_string[j] = temp
+    i += 1
+    j -= 1
+  end
 end
 
 # A method to reverse each word in a sentence, in place.
 def reverse_words(my_words)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  sub_start = 0
+  sub_end = 0
+  while i < my_words.length
+    if my_words[i] != " "
+      until my_words[i] == " " || i == my_words.length
+        i += 1
+      end
+
+      sub_end = i - 1
+
+      while sub_start <= sub_end && i <= my_words.length
+        temp = my_words[sub_start]
+        my_words[sub_start] = my_words[sub_end]
+        my_words[sub_end] = temp
+        sub_end -= 1
+        sub_start += 1
+      end
+
+      sub_start = i
+
+    else
+      i += 1
+      sub_start += 1
+    end
+  end
 end
 
 # A method to reverse the words in a sentence, in place.
 def reverse_sentence(my_sentence)
-  puts "NOT IMPLEMENTED"
+  i = 0
+  j = my_sentence.length - 1
+
+  while i < j
+    temp = my_sentence[i]
+    my_sentence[i] = my_sentence[j]
+    my_sentence[j] = temp
+    i += 1
+    j -= 1
+  end
+
+  i = 0
+  sub_start = 0
+  sub_end = 0
+
+  while i < my_sentence.length
+    if my_sentence[i] == " "
+      i += 1
+      sub_start += 1
+    else
+      until my_sentence[i] == " " || i == my_sentence.length
+        i += 1
+      end
+
+      sub_end = i - 1
+
+      while sub_start <= sub_end && i <= my_sentence.length
+        temp = my_sentence[sub_start]
+        my_sentence[sub_start] = my_sentence[sub_end]
+        my_sentence[sub_end] = temp
+        sub_end -= 1
+        sub_start += 1
+      end
+
+      sub_start = i
+    end
+  end
 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"
-  return true
+  forwards = ""
+  backwards = ""
+
+  j = 0
+  while j < my_phrase.length
+    unless my_phrase[j] == " "
+      forwards << my_phrase[j]
+    end
+    j += 1
+  end
+
+  i = my_phrase.length - 1
+
+  while i >= 0
+    unless my_phrase[i] == " "
+      backwards << my_phrase[i]
+    end
+    i -= 1
+  end
+
+  if forwards == backwards
+    return true
+  else
+    return false
+  end
 end
 
 # 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"
+  first = my_string[0]
+  i = 0
+  count = 0
+  while i < my_string.length
+    until my_string[i] != first || i == my_string.length
+      i += 1
+      count += 1
+    end
+
+    if count > 2
+      my_string[i - count] = first
+      my_string[i - count + 1] = count.to_s
+
+      (count - 2).times do
+        my_string[i - 1] = ""
+        i -= 1
+      end
+    end
+
+    first = my_string[i]
+    count = 0
+  end
 end
 
 ### ---- END OF METHODS
@@ -67,27 +185,27 @@ def encode_repeating(my_string)
 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
+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."