input_and_output.step

goals do
goal "Print to the screen with puts"
goal "Read user input with gets"
end

message ''

step do
  irb "puts 'Hello World'"
  message '`puts` (**put** **s**tring) is a way of printing information to the user of your program.'
  message 'Take some time to contemplate the output of `puts` in irb:'
  result <<-RESULT
    irb :006 > puts 'Hello World'
    Hello World
    => nil
    irb :007 >
  RESULT
  message 'The method `puts` always has the **return value** of `nil`, which is what we see after the `=>` in the output. Printing \'Hello World\' to the screen is just a side-effect.'
end


step do
  message "`print` is like `puts` but doesn't make a new line after printing."

  message 'Create a new file called input\_and\_output.rb'
  type_in_file 'input_and_output.rb', <<-'CONTENTS'
print "All"
print " "
print "in"
print " "
print "a"
print " "
print "row"
CONTENTS
  message "Save the file and exit out of irb."
  console 'ruby input_and_output.rb'
end


step do
  message 'Create a new file called conditionals_test.rb'
  type_in_file 'conditionals_test.rb', <<-'CONTENTS'
print "How many apples do you have? > "
apple_count = gets.to_i
puts "You have #{apple_count} apples."
  CONTENTS
  message "Save the file and exit out of irb."
  console 'ruby conditionals_test.rb'
  message 'When prompted, type in a number of apples and press enter.'
  message "`print` is like `puts` but doesn't make a new line after printing."
  message "`gets`, or **get** **s**tring, pauses your program and waits for the user to type something and hit the enter key. It then returns the value back to your program and continues execution. Since the user could have typed anything ('banana', '19.2', '<<!!@@') we use to_i to ensure what comes out is an integer. If the user didn't type a valid integer, `to_i` returns `0`."
end

challenge do
  message 'Create a program that echoes (or repeats) user input. Use `puts` and `gets` to make this program work.'

  message 'Here is a sample of how the program might run. The `>` has been used below to indicate that the user should input the value proceeding it.'

  source_code <<-'CONTENTS'
What do you want to say?
> sally sells seashells
You said: sally sells seashells
CONTENTS
end
next_step "numbers_and_arithmetic"