code: def execute
        result = eval(operation)      
        if outfile
          if result.is_a?(SpreadSheet)
            result.write(outfile)
          else
            puts
            puts "Warning: Result is no spread sheet and not written to file!"
            puts "         To view the result use -p flag" unless print
          end
        end
  
        if print
          puts
          puts "Operation"
          puts "---------"
          operation.split(';').each { |o| puts o }
          puts
          puts "Result"
          puts "------"
          if result.nil? || result.empty?
            puts result.inspect
          else
            puts result
          end
          puts
        end
      end
docs: Executes the operation and writes the result to the outfile