Pre-class Exercises

What is the difference between the following two lines?

num = 4
num == 4

---

Given the following code:

num = gets.chomp

if num == 4
  puts "Hooray, four is the best!"
elsif num < 0
  puts "Less than zero"
else
  puts "I'm not familiar with that number..."
end

What will happen if the user enters: -1? How about 4? Or 15?

---

If x and y are defined as:

x = 4
y = x

Will the following boolean expressions be true or false? Why?

(x == 4) && (y >= x + 1)
(x == 4) || (y >= x + 1)

What does

!true

mean?