> > I'm learning to progam and came accross Chris Pine's Ruby Tutorial.
> > I've got to the Array and Iterators chapter (Arrays and Iterators - Learn to Program
> > ).
> > and the following assignment " Let's write a program which asks us to
> > type in as many words as we want (one word per line, continuing until
> > we just press Enter on an empty line), and which then repeats the
> > words back to us in alphabetical order. OK? "
> That's all fairly clear....
> > ****** HOWEVER I'm not allowed to use the .sort method ********
> That's also clear, you are writing a sort program to teach you about
> programming, rather than to teach you to explore the library.
> > The covered chapters (1 ~ 7) have not covered method creation,
> > Classes, Blocks or Procs, so the challenge is to solve the assignment
> > without using them ( which is dandy since I don't know what they are
> > and I want to solve this assignment before I move forward to discover
> > what they are).
> OK
> > This is what I've come up with so far, however when run.... It's not
> > working - surprise surprise.
> > Could someone initially give me an idea of what is going wrong rather
> > than rectify my code.
> This is rather difficult. Why?
> You have told us what the outcome of the program should be.
> You have shown us a program that doesn't work.
> There could be several things wrong, including the mental model you
> have built. It would be a big help to us in helping you if you told
> us how you intended the program to work. It may be that you have
> misunderstood something, so expressed your idea poorly in code. Which
> is OK of course, that's the point of learning. It may be that the
> algorithm you have chosen to implement doesn't work, so even if the
> program implements it correctly, you won't get the answer you want..
> So the next thing to learn about programming is that comments are to
> express intention, to give people a bird's eye view of the code so they
> can see what the programmer was trying to do, when that is not immediately
> obvious from the code, or when the code could be wrong, expressing another
> idea.
> Add comments to this to explain your intentions about each major section
> and then we can tell you if your code expresses that intention
> > puts 'Type in as many words as you want and once you\'ve had enough,
> > just \'enter\' a clear line.'
> > words_array =
> > loop do
> > input = gets.downcase.chomp
> > break if input.empty?
> > words_array << input
> > end
> > wordCheck = words_array.last
> > rotateCounter = 0
> > sortedWords_array =
> > until words_array.length == 0
> > while rotateCounter <= words_array.length
> > if words_array[0] >= wordCheck
> > words_array.push words_array.shift
> > rotateCounter = rotateCounter + 1
> > else wordCheck = words_array[0]
> > rotateCounter = 0
> > end
> > end
> > sortedWords_array.push wordCheck
> > until wordCheck = words_array.last
> > words_array.push words_array.shift
> > end
> > words_array.pop
> > rotateCounter = 0
> > wordCheck = words_array.last
> > end
> > puts sortedWords_array
> > # Any help greatly appreciated
> Hugh
# basic mental model - store words in 1st array (words_array). Find
the 'smallest' word alphabetically by selecting the last word (call it
wordCheck) from words_array and compare wordCheck with the first word,
second word and so on..... and exchange the value of wordCheck with
the other word (1st/2nd... word) if the other word value happens to be
less. Start the checking again with the first word, second word....
and so on until a counter has been reached (counter equal to 'current'
length of words_array). Once the counter has been reached, put the
value of wordCheck into a second array (sortedWords_array) and delete
wordCheck value from first unsorted array (words_array) and repeat
until words_array is empty.
puts 'Type in as many words as you want and once you\'ve had enough,
just \'enter\' a clear line.'
words_array = # create 1st array called words_array to store users
unsorted values
loop do
input = gets.downcase.chomp # take the user input, remove the
'enter' off the tail and lower the case and call ...
break if input.empty? # .. it 'input' , break from the loop if
'input' is equal to empty
words_array << input # push 'input' to the words_array
end
wordCheck = words_array.last # wordCheck is equal to the last 'input'
stored in the words_array
rotateCounter = 0
sortedWords_array = # create 2nd array to contain 'sorted' values
until words_array.length == 0 # exit once no words left in the first
unsorted array
while rotateCounter <= words\_array\.length \# exit if rotate counter
greater than words contained within first array
if words_array[0] >= wordCheck # continue if first word in 1st array
greater or equal to wordCheck value
words\_array\.push words\_array\.shift \# rotate the first unsorted
array
rotateCounter = rotateCounter + 1 # add 1 to counter
else wordCheck = words\_array\[0\] \# replace current value \(wordCheck\)
with 'smaller' word
rotateCounter = 0 # reset counter to zero
end
end
sortedWords\_array\.push wordCheck \# add wordCheck value to 2nd array
until wordCheck = words\_array\.last \# rotate first array until a
matching ..
words_array.push words_array.shift # .. value found at the back of
the first array
end
words_array.pop # remove the last value contained within the 1st
array
rotateCounter = 0 # reset rotate counter
wordCheck = words_array.last # replace current value of wordCheck
with new last word from 1st array
end
puts sortedWords_array # print values within 2nd array, which should
be in low to high alphabetical order
# Hope the above is legible
> [lots of stuff worth trimming]
# basic mental model - store words in 1st array (words_array). Find
the 'smallest' word alphabetically by selecting the last word (call it
wordCheck) from words_array and compare wordCheck with the first word,
second word and so on..... and exchange the value of wordCheck with
the other word (1st/2nd... word) if the other word value happens to be
less. Start the checking again with the first word, second word....
and so on until a counter has been reached (counter equal to 'current'
length of words_array). Once the counter has been reached, put the
value of wordCheck into a second array (sortedWords_array) and delete
wordCheck value from first unsorted array (words_array) and repeat
until words_array is empty.
I think this should work. You will learn more efficient ways to do
this,
but this is a good start. Knuth recommends thinking about how to
solve
sorting problems yourself first, before consulting other algorithms.
- Hide quoted text -
- Show quoted text -
puts 'Type in as many words as you want and once you\'ve had enough,
just \'enter\' a clear line.'
words_array = # create 1st array called words_array to store users
unsorted values
loop do
input = gets.downcase.chomp # take the user input, remove the
'enter' off the tail and lower the case and call ...
break if input.empty? # .. it 'input' , break from the loop if
'input' is equal to empty
words_array << input # push 'input' to the words_array
end
wordCheck = words_array.last # wordCheck is equal to the last 'input'
stored in the words_array
rotateCounter = 0
sortedWords_array = # create 2nd array to contain 'sorted' values
until words_array.length == 0 # exit once no words left in the first
unsorted array
while rotateCounter <= words_array.length # exit if rotate counter
greater than words contained within first array
if words_array[0] >= wordCheck # continue if first word in 1st array
greater or equal to wordCheck value
words_array.push words_array.shift # rotate the first unsorted
array
rotateCounter = rotateCounter + 1 # add 1 to counter
else wordCheck = words_array[0] # replace current value (wordCheck)
with 'smaller' word
rotateCounter = 0 # reset counter to zero
end
end
sortedWords_array.push wordCheck # add wordCheck value to 2nd array
until wordCheck = words_array.last # rotate first array until a
matching ..
words_array.push words_array.shift # .. value found at the back of
the first array
end
words_array.pop # remove the last value contained within the 1st
array
rotateCounter = 0 # reset rotate counter
wordCheck = words_array.last # replace current value of wordCheck
with new last word from 1st array
end
puts sortedWords_array # print values within 2nd array, which should
be in low to high alphabetical order
# Hope the above is legible
So, what output do you get that is wrong? This code works for me, for
the input "words"
a
b
a
c
a
b
Hugh
If I use the following input [ q w e r t y ] I end up with [ e q r t w
w ] and the input [ z x c v b ] end up as [ b b b b b ].
If my mental model is o.k, then my code must be wrong, but I'm stumped
at to where.
Thank you all for your time so far.
···
On 25 Nov, 21:20, jgh...@googlemail.com wrote:
On Nov 25, 2:37 pm, Hugh Sasse <h...@dmu.ac.uk> wrote:
> On Tue, 25 Nov 2008, jgh...@googlemail.com wrote:
On Wed, 26 Nov 2008, jgh...@googlemail.com wrote:
On Nov 25, 2:37 pm, Hugh Sasse <h...@dmu.ac.uk> wrote:
or Sorting by minimum search