Ruby while Loop

The Ruby while loop is used to iterate a program several times. If the number of iterations is not fixed for a program, while loop is used.

Ruby while loop executes a condition while a condition is true. Once the condition becomes false, while loop stops its execution.

Syntax:

while conditional [do]  

   code  

end

Example:

#!/usr/bin/ruby   

x = gets.chomp.to_i   

while x >= 0    

  puts x   

  x -=1   

end

Output:

---

Ruby do while Loop

The Ruby do while loop iterates a part of program several times. It is quite similar to a while loop with the only difference that loop will execute at least once. It is due to the fact that in do while loop, condition is written at the end of the code.

Syntax:

loop do   

  #code to be executed  

  break if booleanExpression  

end

Example:

loop do   

  puts "Checking for answer"   

  answer = gets.chomp   

  if answer != '5'   

    break   

  end   

end

Output: