Ruby-Code

=begin
 Binary to decimal converter and reverse
 By Lars I.
 for Train-your-Programmer
 Link: https://trainyourprogrammer.de/ruby  #168
 lines of code: 23
=end

#=============================================================================

def getBinary()
=begin
 In:
  nothing
 Out:
  returns the entered binary number as a string
=end

#Section - Code
 #Section - Declaration
    input_okay = true
    bin = ""
    
 #Section - getting and checking the user-input
    loop do
        puts "Please enter your binary number."
        print "Your input = "
        bin = gets.chomp
        print "\n\n===============================================================================\n\n"
        
        #validating the input
        bin.each_char do |x| #filling the array with the single digits of the binary number
            if x != "0" && x != "1" #x == "0" || x == "1"
                #arr.push(x)
            #else
                input_okay = false
                break
            end
        end
        
        #breaking the loop if only 0's and 1's have been entered
        break if input_okay == true
    end
    
 #Section - Output
    return bin
end

#=============================================================================

def convert()
=begin
 In:
  nothing
 Out:
  nothing
=end

#Section - Code
 #Section - Get the number to be converted
    bin = getBinary()
    
 #Section - Converting the binary to a decimal number
    dec = bin.to_i(2)
    
 #Section - Output
    puts "The binary number #{bin} matches #{dec} in the decimal number system."
end

convert()