控制流程 python

Question

实际上我习惯了 c++ 并且我被困在 python 中。 我似乎无法理解导致无限 while 循环的原因。 该代码的主要目标是计算需要多少个月才能节省足够的钱用于预付款。

#*******Initializing all the required variables***********
home_price = float(input("Enter the price of your dream home:")) # cost of the home

down_payment_portion = 0.25 # initial upfront pay for the home which is 25%
stamp_duty_portion = 0.03 # 3%

annual_salary = float(input("Enter your annual salary:"))

tax_portion = 0.2 # 20%
save_amount = 0

save_portion = float(input("Enter the amount of money you want to save after tax-cut:"))

annual_return = 0.05 # 5%
months = 0

#*********************************************************
#------------Calculating all the necessary values---------

down_payment_portion = down_payment_portion * home_price # calculating the down payment for the dream home

stamp_duty_portion = stamp_duty_portion * home_price # calculating the stamp duty for the home

tax_portion = tax_portion * annual_salary # calculating the tax cut

save_portion = save_portion * save_amount # calculating the portion of tax-cut income to be put into savings

annual_return = (save_amount * annual_return) / 12

upfront_payment = down_payment_portion + stamp_duty_portion

while(save_amount < upfront_payment):
   save_amount = save_amount + annual_return
   save_amount = save_amount + (annual_salary - tax_portion) * save_portion / 12
   months = months + 1

print(f'You will need {months} month to save enough for your upfront payment{upfront_payment}.')

Answer 1

1. 你初始化save_amount = 0
2. 你得到annual_return为annual_return = (save_amount * annual_return) / 12 ，这将是零
3. 你还得到save_portion作为save_portion = save_portion * save_amount再次为零
4. 因此，您在while 循环中的save_amount永远不会增加它也保持为零， save_amount < upfront_payment始终为 true ==> 无限循环

在您的代码中

while(save_amount < upfront_payment):
   save_amount = save_amount + annual_return # 0 + 0 = 0

   # 0 + (some value * 0)/12 = 0
   save_amount = save_amount + (annual_salary - tax_portion) * save_portion / 12