def getProperStringValue(message, requiredLength):
  value = ""
  while len(value)<requiredLength:
    value = input(message)
    if len(value)<requiredLength:
      print("You're string is too short. You need to give at least", requiredLength, "characters!")
  return value

def getProperIntValue(message, minimum):
  value = None
  while not value:
    try:
      value = int(input(message))
      if value<minimum:
        print("You have to be above", minimum ,"age")
        value = None
    except:
      print("Age has to be an integer!")
      value = None
  return value

def getProperHeight(message, minimum, maximum):
  value = None
  while not value:
    try:
      value = int(input(message))
      if value<minimum:
        print("You have to be above", minimum ,"cm height")
        value = None
      if value>maximum:
        print("You have to be below", maximum ,"cm height")
        value = None
    except:
      print("Height has to be an integer!")
      value = None
  return value

while True:
  username = getProperStringValue("Type in your username: ", 1)
  password = getProperStringValue("Type in your password: ", 5)
  age = getProperIntValue("Type in your age: ", 16)
  height = getProperHeight("Type in your height: ", 100, 250)

  with open('output.txt', 'a') as file:
    file.write("User: " + username + "\nPassword: " + password + "\nAge: " + str(age) + "\nHeight: " + str(height) + " cm\n")
    print("Username has been created correctly!\n")