learn to program

ch09-writing-your-own-methods/ask.rb

@@ -1,3 +1,14 @@
 def ask question
-  # your code here
+    # your code here
+    while true
+        puts question
+        reply = gets.chomp.downcase
+        if (reply == 'yes' || reply == 'no')
+            if reply == 'yes'
+                return true
+            else
+                return false
+            end
+        end
+    end
 end

ch09-writing-your-own-methods/old_school_roman_numerals.rb

@@ -1,3 +1,17 @@
 def old_roman_numeral num
-  # your code here
+    # your code here
+    num = num.to_i
+    (puts "Invalid input. Choose a number between 1 and 3000"; return) if ((num.to_i < 1) || (num.to_i > 3000))
+
+    numerals = {1000=>"M", 500=>"D", 100=>"C", 50=>"L", 10=>"X", 5=>"V", 1=>"I" }
+    roman = ""
+
+    numerals.keys.each do |k|
+        n = num/k
+        if n > 0
+            roman += (numerals[k]*n)
+            num = num % k
+        end
+    end
+  return roman
 end

ch09-writing-your-own-methods/roman_numerals.rb

@@ -1,3 +1,18 @@
 def roman_numeral num
-  # your code here
+    # your code here
+    num = num.to_i
+    (puts "Invalid input. Choose a number between 1 and 3000"; return) if ((num.to_i < 1) || (num.to_i > 3000))
+
+    numerals = {1000=>"M", 500=>"D", 400=>"CD", 100=>"C", 90=>"XC", 50=>"L", 40=>"XL", 10=>"X", 9=>"IX", 5=>"V", 4=>"IV", 1=>"I" }
+    roman = ""
+
+    numerals.keys.each do |k|
+        n = num/k
+        if n > 0
+            roman += numerals[k]*n
+            num = num % k
+        end
+    end
+
+  return roman
 end

ch10-nothing-new/dictionary_sort.rb

@@ -1,3 +1,22 @@
 def dictionary_sort arr
   # your code here
+  return recursive_sort(arr, [])
+end
+
+def recursive_sort(unsorted_array, sorted_array)
+    return sorted_array if unsorted_array.empty?
+    #l = unsorted_array.length-1
+    smallest = unsorted_array.pop
+    unsorted2 = []
+    unsorted_array.each do |check|
+        if check.downcase < smallest.downcase
+            unsorted2 << smallest
+            smallest = check
+        else
+            unsorted2 << check
+        end
+    end
+    sorted_array << smallest
+
+    recursive_sort(unsorted2, sorted_array)
 end

ch10-nothing-new/english_number.rb

@@ -1,3 +1,123 @@
 def english_number number
-  # your code here
+  if number < 0  # No negative numbers.
+    return 'Please enter a number that isn\'t negative.'
+  end
+  if number == 0
+    return 'zero'
+  end
+
+  # No more special cases! No more returns!
+
+  numString = ''  # This is the string we will return.
+
+  onesPlace = ['one',     'two',       'three',    'four',     'five',
+               'six',     'seven',     'eight',    'nine']
+  tensPlace = ['ten',     'twenty',    'thirty',   'forty',    'fifty',
+               'sixty',   'seventy',   'eighty',   'ninety']
+  teenagers = ['eleven',  'twelve',    'thirteen', 'fourteen', 'fifteen',
+               'sixteen', 'seventeen', 'eighteen', 'nineteen']
+  nums = {'quindecillion'=>10**48, 'quattuordecillion'=>10**45, 'tredecillion'=>10**42, 'duodecillion'=>10**39, 'undecillion'=>10**36,
+  'decillion'=>10**33, 'nonillion'=>10**30, 'octillion'=>10**27, 'septillion'=>10**24, 'sextillion'=>10**21, 
+  'quintillion'=> 10**18, 'quadrillion'=> 10**15, 
+  'trillion'=> 10**12, 'billion'=> 10**9, 'million'=> 10**6, 'thousand'=> 10**3, 'hundred'=> 10**2 }
+
+  # "left" is how much of the number we still have left to write out.
+  # "write" is the part we are writing out right now.
+  # write and left... get it?  :)
+  left  = number
+
+nums.each do |name,value|
+  #print name
+  write = left/value         # How many millions left to write out?
+  left  = left - write*value  # Subtract off those millions.
+
+if write > 0
+    # trillions
+    trillions  = english_number write
+    numString = numString + (english_number write) + " " + name.to_s
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ' '
+    end
+  end
 end
+
+=begin
+write = left/1000000000000          # How many millions left to write out?
+  left  = left - write*1000000000000  # Subtract off those millions.
+
+  if write > 0
+    # Now here's a really sly trick:
+    hundreds  = english_number write
+    numString = numString + hundreds + ' hundred'
+    # That's called "recursion". So what did I just do?
+    # I told this method to call itself, but with "write" instead of
+    # "number". Remember that "write" is (at the moment) the number of
+    # hundreds we have to write out. After we add "hundreds" to
+    # "numString", we add the string ' hundred' after it.
+    # So, for example, if we originally called english_number with
+    # 1999 (so "number" = 1999), then at this point "write" would
+    # be 19, and "left" would be 99. The laziest thing to do at this
+    # point is to have english_number write out the 'nineteen' for us,
+    # then we write out ' hundred', and then the rest of
+    # english_number writes out 'ninety-nine'.
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ' '
+    end
+  end
+=end
+#### ------------> TENS
+
+  write = left/10          # How many tens left to write out?
+  left  = left - write*10  # Subtract off those tens.
+
+  if write > 0
+    if ((write == 1) and (left > 0))
+      # Since we can't write "tenty-two" instead of "twelve",
+      # we have to make a special exception for these.
+      numString = numString + teenagers[left-1]
+      # The "-1" is because teenagers[3] is 'fourteen', not 'thirteen'.
+
+      # Since we took care of the digit in the ones place already,
+      # we have nothing left to write.
+      left = 0
+    else
+      numString = numString + tensPlace[write-1]
+      # The "-1" is because tensPlace[3] is 'forty', not 'thirty'.
+    end
+
+    if left > 0
+      # So we don't write 'sixtyfour'...
+      numString = numString + '-'
+    end
+  end
+
+  write = left  # How many ones left to write out?
+  left  = 0     # Subtract off those ones.
+
+  if write > 0
+    numString = numString + onesPlace[write-1]
+    # The "-1" is because onesPlace[3] is 'four', not 'three'.
+  end
+
+  # Now we just return "numString"...
+  return numString
+end
+
+puts english_number(  0)
+puts english_number(  9)
+puts english_number( 10)
+puts english_number( 11)
+puts english_number( 17)
+puts english_number( 32)
+puts english_number( 88)
+puts english_number( 99)
+puts english_number(100)
+puts english_number(101)
+puts english_number(234)
+puts english_number(3211)
+puts english_number(999999)
+puts english_number(1000000000000)

ch10-nothing-new/ninety_nine_bottles_of_beer.rb

@@ -1 +1,176 @@
-# your code here
+=begin
+https://pine.fm/LearnToProgram/chap_08.html
+
+Expand upon englishNumber. First, put in thousands. 
+So it should return 'one thousand' instead of 'ten hundred' 
+and 'ten thousand' instead of 'one hundred hundred'.
+Expand upon englishNumber some more. 
+Now put in millions, so you get 'one million' instead of 
+'one thousand thousand'. Then try adding billions and trillions. 
+How high can you go? 
+
+=end
+
+
+def weddingNumber number
+  if number < 0  # No negative numbers.
+    return 'Please enter a number that isn\'t negative.'
+  end
+  if number == 0
+    return 'zero'
+  end
+
+  # No more special cases! No more returns!
+
+  numString = ''  # This is the string we will return.
+
+  onesPlace = ['one',     'two',       'three',    'four',     'five',
+               'six',     'seven',     'eight',    'nine']
+  tensPlace = ['ten',     'twenty',    'thirty',   'forty',    'fifty',
+               'sixty',   'seventy',   'eighty',   'ninety']
+  teenagers = ['eleven',  'twelve',    'thirteen', 'fourteen', 'fifteen',
+               'sixteen', 'seventeen', 'eighteen', 'nineteen']
+
+  # "left" is how much of the number we still have left to write out.
+  # "write" is the part we are writing out right now.
+  # write and left... get it?  :)
+  left  = number
+
+#### ------------> TRILLIONS
+
+write = left/1000000000000          # How many millions left to write out?
+  left  = left - write*1000000000000  # Subtract off those millions.
+
+if write > 0
+    # trillions
+    trillions  = weddingNumber write
+    numString = numString + trillions + ' trillion'
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ' and '
+    end
+  end
+
+#### ------------> BILLIONS
+
+write = left/1000000000          # How many millions left to write out?
+  left  = left - write*1000000000  # Subtract off those millions.
+
+if write > 0
+    # billions
+    billions  = weddingNumber write
+    numString = numString + billions + ' billion'
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ' and '
+    end
+  end
+
+#### ------------> MILLIONS
+  write = left/1000000          # How many millions left to write out?
+  left  = left - write*1000000  # Subtract off those millions.
+
+if write > 0
+    # millions
+    millions  = weddingNumber write
+    numString = numString + millions + ' million'
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ' and '
+    end
+  end
+
+#### ------------> THOUSANDS
+
+  write = left/1000          # How many thousands left to write out?
+  left  = left - write*1000  # Subtract off those thousands.
+
+if write > 0
+    # for thousands
+    hundreds  = weddingNumber write
+    numString = numString + hundreds + ' thousand'
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ', '
+    end
+  end
+
+#### ------------> HUNDREDS
+
+  write = left/100          # How many hundreds left to write out?
+  left  = left - write*100  # Subtract off those hundreds.
+
+  if write > 0
+    # Now here's a really sly trick:
+    hundreds  = weddingNumber write
+    numString = numString + hundreds + ' hundred'
+    # That's called "recursion". So what did I just do?
+    # I told this method to call itself, but with "write" instead of
+    # "number". Remember that "write" is (at the moment) the number of
+    # hundreds we have to write out. After we add "hundreds" to
+    # "numString", we add the string ' hundred' after it.
+    # So, for example, if we originally called englishNumber with
+    # 1999 (so "number" = 1999), then at this point "write" would
+    # be 19, and "left" would be 99. The laziest thing to do at this
+    # point is to have englishNumber write out the 'nineteen' for us,
+    # then we write out ' hundred', and then the rest of
+    # englishNumber writes out 'ninety-nine'.
+
+    if left > 0
+      # So we don't write 'two hundredfifty-one'...
+      numString = numString + ' and '
+    end
+  end
+
+#### ------------> TENS
+
+  write = left/10          # How many tens left to write out?
+  left  = left - write*10  # Subtract off those tens.
+
+  if write > 0
+    if ((write == 1) and (left > 0))
+      # Since we can't write "tenty-two" instead of "twelve",
+      # we have to make a special exception for these.
+      numString = numString + teenagers[left-1]
+      # The "-1" is because teenagers[3] is 'fourteen', not 'thirteen'.
+
+      # Since we took care of the digit in the ones place already,
+      # we have nothing left to write.
+      left = 0
+    else
+      numString = numString + tensPlace[write-1]
+      # The "-1" is because tensPlace[3] is 'forty', not 'thirty'.
+    end
+
+    if left > 0
+      # So we don't write 'sixtyfour'...
+      numString = numString + '-'
+    end
+  end
+
+  write = left  # How many ones left to write out?
+  left  = 0     # Subtract off those ones.
+
+  if write > 0
+    numString = numString + onesPlace[write-1]
+    # The "-1" is because onesPlace[3] is 'four', not 'three'.
+  end
+
+  # Now we just return "numString"...
+  numString
+end
+
+
+def ninety_nine_bottles_of_beer num
+while (num > 0)
+  puts weddingNumber(num) + " bottles of beer on the wall, " + weddingNumber(num) + " bottles of beer."
+  puts "Take one down and pass it around, " + weddingNumber(num-1) + " bottles of beer on the wall."
+  num -= 1
+end
+end
+
+ninety_nine_bottles_of_beer 99