integer.rb

class Integer

  def to_base(base)
    number = self.abs
    result = ''
    digits = (0..9).to_a + ('A'..'Z').to_a
    
    raise "Sorry, there aren't enough characters to convert #{number} to base #{base}" if base > digits.size
  
    while number > 0
      result = digits[number % base].to_s + result
      number = number / base
    end   
  
    self<0 ? "-#{result}" : result
  end
  
  def to_twos_complement(bitsize = 16)
    self < 0 ? (self + 2**bitsize).to_base(2) : to_base(2).rjust(bitsize, '0')
  end

end

uebung1.rb

puts "c)\n\n"
for base in [2,8,16,13]
  puts "Umrechnung zur Basis #{base}"
  for number in [93, 10000, 32768, 314171, 1048576]
    puts "Die Zahl #{number} ergibt zur Basis #{base}: #{number.to_base(base)}"
  end
  puts "\n"
end

puts "d)\n\n"
for number in [-1, 1, 57, -84, -256, 257]
  puts "Die Zahl #{number} ergibt in Zweierkomplementdarstellen: #{number.to_twos_complement}"
end