loops.rb

# while loop runs until a condition is false
num = 10
while num > 0 do
  puts "value of num is now: #{num}"
  num -= 1
end

# until is similar to the while loop, runs until the condition is false
i = 0
until i >= 10 do
  puts "value of i: #{i}"
  i += 1
end

# range
(1..5) # values from 1 upto 5, double dots include the upper value
(1...5) # values from 1 upto 4, tripple dots exclude the upper value

# the for loop is used to loop through a collection of items
my_letters_array = ['a', 'b', 'c', 'd']
for i in 0...my_letters_array.length
  puts "#{my_letters_array[i]}"
end

# .times loop, this runs a loop a given number of times
i = 0
5.times do
  puts "this is printed #{i + 1} times"
  i += 1
end

3.times do |number|
  puts "Print time: #{number + 1}"
end

=begin
1. upto loop is used to loop up to a specific value
2. downto loop is used to loop down to a specific value
=end

# this loop prints values from 0 upto 5 -- ie lowers to highest
0.upto(5) do |num|
  puts num
end
print "----------------------------\n"
# this loop prints values from 5 to 0 ie highest to lowest
5.downto(0) do |num|
  puts num
end