03.rb

#錯誤處理 throw exception
def bmi(w, h)
  w / (h * h)
rescue => exception
  "enter error number"
end

p bmi(1, 0)

#迴圈的處理loop
10.times do
  puts "hello world"
end

#do..end or {} == Block
#same
p 1.upto(5) { |i| puts i }
#same
1.upto(5) do |i|
  puts i
end

p 5.downto(1) { |i| puts i }

5.downto(1) do |i|
  puts i
end

#迭代的處理lteration
array = [1, 2, 3, 4, 5]
for i in array
  if (i == 3)
    puts "get it #{i}"
    break
  end
end

x = 0
while x < 10
  puts x
  x += 1
end

y = 0
#until = while not
until y >= 10
  puts y
  y += 1
end

i = 0
loop do
  puts i
  i += 1
  break if i > 10
end

names = ["a", "b", "c"]
#each
names.each { |name| puts name }
#each
names.each do |name|
  puts name
end
#each with index
names.each.with_index do |name, x|
  puts "#{x}, #{name}"
end