Ruby: Decisions

Ruby supports numerous ways to construct decision statements:

  • if statement
  • if modifier
  • unless statement
  • unless modifier
  • case statement

Example: IF Statement in Ruby

	score = 219
	if score == 300
	   puts "Perfect game."
	elsif score >= 200
	   puts "Great game"
	elsif score >= 150
	   puts "Good game"
	   puts "Keey practicing"


  Great game

Example: Ruby if modifier

	$flag = 1
	print "Run this code\n" if $flag
	print "Run this code too\n" if $flag2


  Run this code

The Ruby if modifier runs the code before it only if the condition is true (in this case when the flag is set/true). Notice how the second output line does not run.

Example: Ruby unless Statement

	x = 51
	unless x >= 50
	   puts "x is less than 50"
	   puts "x is greater than 50"


  Run this code

The Ruby unless statement executes code if conditional is false. If the conditional is true, code specified in the else clause is executed.