I’m trying to duplicate the RPN caculator code found Here. When I run my code I get an Error: undefined method `evaluate’ for main:Object (NoMethodError)
Any suggestions? It does not seem that the author would put up faulty code on her website.
class RPNCalculator def evaluate(expression) expression = expression.split operands =  evaluation =  expression.each do |x| case x when /\d/ evaluation.push(x.to_f) when "-", "/", "*", "+", "**" operands = evaluation.pop(2) evaluation.push(operands.send(x, operands)) end end puts evaluation end end input = "112++" evaluate(input)