没有得到正确的输出…logi

Question

我的代码给出了正确的结果，除了balance=3926。最低付款：370，而应该是360。程序应打印给定年利率的最低月供。给定初始余额，代码应在年底计算余额。我们正试着每月付10美元的初始余额。如果年底还有余额，我们会编写代码，将余额重置为初始余额，将付款增加10美元，然后重试（使用相同的代码！）计算年底的余额，看看这个新的支付值是否足够大

annualInterestRate = 0.2

balance = 3926

monthlyinterestrate = annualInterestRate/12.0

remainingBalance = balance

month = 1
total = 0

payment = 10

def CheckMinimumPayment(payment,balance):

    "Checking if payment is in correct balance"
    while(payment*12 < balance):

        payment += 10
    return payment

payment = CheckMinimumPayment(payment,balance)

while(month <= 12):
    remainingBalance = remainingBalance - payment + (annualInterestRate / 12.0) * (remainingBalance - payment)
    month += 1
    total += payment


payment = CheckMinimumPayment(payment,total+remainingBalance)

print("Lowest Payment: " + str(payment))

Answer 1

问题是，每次尝试新的支付时，您不会重复利息循环（您所拥有的while(month <= 12)）。把这个循环写进一个函数中，每次你尝试新的支付时都会调用它。总的欠款余额取决于还款情况，因为每月的大额还款意味着每月增加的利息减少。我用的是：

annualInterestRate = 0.2
init_balance = 3926

monthlyInterestRate = annualInterestRate/12.0
init_payment = 10

def owedBalance(payment,balance):
    """ Calculate total owed balance after one year
        given an initial balance and montly payment"""

    for month in range(12):
        balance = (balance - payment) * (monthlyInterestRate + 1)

    return payment*12 + balance

def CheckMinimumPayment(payment,balance):
    "Checking if payment is in correct balance"

    while (payment*12 < owedBalance(payment, balance)):
        payment += 10

    return payment

min_payment = CheckMinimumPayment(init_payment,init_balance)

print("Lowest Payment: {}".format(min_payment))