cont = "y"
while (cont == "y")
    print ("Enter a numerator: ")
    num = Integer(gets)
    print("Enter a denominator: ")
    denom = Integer(gets)
    if denom == 0 then
        next 
        # or 'redo'
        # or 'break' to exit
    end
    puts(num / denom)
    print ("More? (y/n) ")
    cont = gets
    cont = cont.chomp
end

answer = "Watson"
tries = 0
while tries < 3
    print("What is the name of the computer that played on Jeopardy? ")
    response = gets
    response = response.chomp
    tries += 1
    if response == "Watson"
        puts ("That's right!")
        exit
    elsif tries == 3
        puts ("Sorry. The answer is Watson.")
        exit
    else
        puts ("Sorry. Try again")
    end
end

" now's  the time".split        #=> ["now's", "the", "time"]
" now's  the time".split(' ')   #=> ["now's", "the", "time"]
# split by word
" now's  the time".split(/ /)   #=> ["", "now's", "", "the", "time"]

"1, 2.34,56, 7".split(%r{,\s*}) #=> ["1", "2.34", "56", "7"]
# split by letter
"hello".split(//)               #=> ["h", "e", "l", "l", "o"]

"hello".split(//, 3)            #=> ["h", "e", "llo"]
"hi mom".split(%r{\s*})         #=> ["h", "i", "m", "o", "m"]

# 1.
# a block do nothing
# use {} for a single line
{ puts "Echo"}

# associate with a method call
3.times { puts "Echo"}

# 2. Use do-end for multiple lines
10.times do
    puts "situp"
end

# 3. (count from 0-9)
10.times do |number|
    puts "#{number} situp"
end

# 4. (count from 1-10)
1 upto(10) do |number|
    puts "#{number} situp"
end

# 5.
movies. each do |movie|
    movie.thumbs_up
    puts movie
end

numbers.select do |number| 
    number>5
end

numbers.select{ |number| number>5 }

numbers.select{ |n| n>5}

require_relative 'movie'

describe Movie do
    before do
        @initial_rank = 10
        @movie = Movie.new("goonies", @initial_rank)
    end

    it "has a capitalized title" do
        @movie.title.should == "Goonies"
    end

    it "has an initial rank" do
        @movie.rank.should == 10
    end

    it "has a string representation" do
        @movie.to_s.should == "Goonies has a rank of 10"
    end

    it "increases rank by 1 when given a thumbs up" do
        @movie.thumbs_up
        @movie.rank.should == @initial_rank + 1
    end

    it "decreases rank by 1 when given a thumbs down" do
        @movie.thumbs_down
        @movie.rank.should == @initial_rank - 1
    end

    context "created with a default rank" do
        before do
        @movie = Movie.new("goonies")
        end

        it "has a rank of 0" do
            @movie.rank.should == 0
        end 
    end
end

$ rspec movie_spec.rb --color --format doc

$ rspec . --color

begin
  print("Enter numerator: ")
  num = Integer(gets)
  print("Enter denominator: ")
  denom = Integer(gets)
  ratio = num / denom
  print(ratio)
rescue
    print $! #print error
    puts
    print("Enter a denominator other than 0: ")
    denom = Integer(gets)
    ratio = num / denom
    print(ratio)
end

begin
  print(3/0) # or print(3/1) to show the second error
  File.open("myfile.txt")
#rescue ZeroDivisionError
#  print("tried to deivide by 0")
# or
rescue ZeroDivisionError => oops
  print(oops)
rescue SystemCallError
  print("file not found")
end

print("In program")
raise "exception raised"
print("Back in program")

# ex 1
def inverse(x)  
  raise ArgumentError, 'Argument is not numeric' unless x.is_a? Numeric  
  1.0 / x  
end  
puts inverse(2)  
puts inverse('not a number')  


# ex 2
def ctof(temp)
  raise ArgumentError, "argument is not numeric" unless temp.is_a? Numeric
  return (9.0/5.0) * temp + 32.0
end

puts ctof(4)
puts ctof('not a number')

# ex 3
def ctof(temp)
  raise ArgumentError, "argument is not numeric" unless temp.is_a? Numeric
  return (9.0/5.0) * temp + 32.0
end

begin
  print("Enter a temperature to convert: ")
  t = Integer(gets)
  print(ctof(t))
rescue
  print("Argument was not a number")
end

alist = [6,1,10,5,9,3,8,4,7,2]
passnum = alist.length-1
catch (:stop) do # catch here
  while passnum > 0
    for i in 0..passnum-1
      print(alist[i])
      if i > 6
        throw :stop # throwing here
      end
    end
  passnum - 1
  end
end

begin
  print("Name of file? :")
  name = gets
  myFile = File.open(name.chomp)
  lines = myFile.read
  puts lines
rescue
  print("File not found. Enter another name.")
  retry # this will take back to 'begin'.
end

$ touch text.txt
$ vim text.txt
line 1
line 2
line 3
line 4
:wq!
$ ruby list.rb

while line = gets
  puts line
end

# to read a file
ruby readfile.rb data.txt

File.open("data.txt") do |file|
  while line = file.gets
    puts line
  end
end

$ ruby readfile.rb

outfile = File.new("myfile.txt","w") # w is for writing
outfile.print("Hello, world\n")
outfile.print("Goodbye, world!")
outfile.close

require 'socket' # socket library for tcp 

host = 'localhost'
port = 1500

sock = TCPSocket.open(host, port) # open the socket with host and port number.

while line = sock.gets
  puts line.chop
end

sock.close

require 'socket'

server = TCPServer.open(1500) # open the port
loop {
    client = server.accept
    client.puts("Hello, client!")
    client.puts("Goodby, client!")
    client.puts("closing connection...")
    client.close
}

$ ruby server.rb #first run the server
# open a tab and run a client
$ ruby client.rb
# This will display the content from the server.rb

count = 0
total = 0
while temp = gets
  total += Integer(temp)
  count += 1
end
puts total / count

tempfile = File.open("temps.txt","a+") # append to the file
day = 1
while day < 8
  print("Enter temperature: ")
  temp = gets
  tempfile.puts(temp)
  day += 1
end
tempfile.close

$ ruby addtemps.rb
# add number one by one
# check it by open it.
$ cat temps.txt
$ ruby tempavg.rb temps.txt

nums = [1,2,3,4,5]
for i in nums
  print (i, i*i)
end

$ ruby -r debug debug1.rb # -r means require switch
# This will show the first line. 
# By typing l and enter you can list with the whole programe with number lines.
# n and enter shows line by line. And this will show the output in front of debug.

nums = [5,2,8,3,1,6]
min = 5
for i in nums
  if i > min # intentional bug. this is supposed to be if i < min
    min = i
  end
end
print("The minimum value is ", min)

$ ruby -r debug debug2.rb
$ n # to show the next line.
$ disp min # this will display min value
# each time when you disp min, it will add 1,2 etc and display min.
# You just need to do it once.
# by using b 6, it will set a break at 6

# fibonacci sequence
t1 = 0
t2 = 1
n = 10
print(0, " ", 1, " ")
while n > 0
  t = t1 + t2
  print(t, " ")
  temp = t2
  t2 = t
  t1 = temp
  n -= 1
end

$ ruby -r debug debug3.rb
$ watch n ==1
Set watchpoint 1:n==1 
# program will run until this watchpoint becomes true.
$ c # c to continue
0 1 1 2 3 5 8 13 21 34 55 Watchpoint 1, toplevel at debug3.rb:7
# the program stopped when n==1 and displayed.

$ ruby -r debug debug3.rb
# run for a few times by n
# then type var local
$ var local # to display all variable at that time
# run it again by typing n
$ v l # same as var local
$ quit # to quit debug

# this will create an infinite loop. It is not increasing pos += 1
nums = [1,3,4,6,2,5]
max = 0
pos = 1
while pos <= nums.length # supposed to be while pos < nums.length
  if nums[pos] > nums[max]
    max = pos
  end
  # pos += 1 # through debugging you can uncomment this.
end
print(nums[max])

require 'tk'

root = TkRoot.new(title "First Example")
TkLabel.new(root) do
  text 'A sample GUI using Tk'
  pack { padx 15; pady 15; side 'left'}
end
Tk.mainloop

cd `brew --prefix`
git fetch origin
git reset --hard origin/master
brew update
brew install glib
brew install gtk+
sudo gem install gtk2