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"
	else
	   puts "Keey practicing"
	end
	

Output:

  Great game

Example: Ruby if modifier

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

Output:

  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"
	 else
	   puts "x is greater than 50"
	end
	

Output:

  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.