1. program to demonstrate if statement

#!/usr/bin/ruby

x = 1
if x == 1
  puts "x is equal to 1"
end

2. program to demosntrate if else statement

#!/usr/bin/ruby

x = 10
if x == 1
  puts "x is equal to 1"
else
  puts "x is not equal to 1"
end

3. program to demonstrate elseif statement

#!/usr/bin/ruby

x = 20
if x > 2
  puts "x is greater than 2"
elsif x <= 2 and x>=1
  puts "x is 1 or 2"
else
  puts "x is 0"
end

4. program to demonstrate unless statement

#!/usr/bin/ruby

x = 1 
unless x>=2
   puts "x is less than 2"
 else
   puts "x is greater than 2"
end

5. program to demonstrate case statement

#!/usr/bin/ruby

$day =  5
case $day
when 1
  puts "monday"
when 2
  puts "tuesday"
when 3
  puts "wednesday"
when 4
  puts "thursday"
when 5
  puts "friday"
when 6
  puts "saturday"
when 7
  puts "sunday"
else
  puts "enter day between 1 to 7"
end