關於不改變N

Question

的問題是價值找到你需要的時候，要到一家信用卡公司的固定金額 -

• BAL =量，你需要在第0個月
年初支付
• N =但是要支付給信用卡公司每月固定金額，使得在今年年底，你將支付的總金額信用卡公司

的

INT =利率

bal = int(raw_input("Enter balance")) 
rate = int(raw_input("enter rate")) 
lower_b = bal/12 
upper_b = (bal + ((rate*bal)/1200))/12 
N= (lower_b+upper_b)/2 
def Credit(bal,rate,N): 
     global upper_b 
     global lower_b 
     i=1 
     k=bal 
     while (i<13): 
      print(N) 
      paid = N 
      bal = bal - paid 
      print("Balance remains to be paid is %s" %(round(bal,2))) 
      Interest = rate * bal /1200 
      print("The interest added on is %s" %(round(Interest,2))) 
      bal=bal+Interest 
      print ("The amount that needs to be payed is %s " %(round(bal,2))) 
      i=i+1 

     if bal==0: 
      return N 
     elif 50 < bal < 2000 : 
      lower_b = N 
      upper_b = upper_b 
      N = (upper_b +lower_b)/2 
      return Credit(k,rate,N) 
     elif -2000<bal< -50: 
      upper_b = N 
      lower_b = lower_b 
      N = (lower_b +upper_b)/2 
      return Credit(k,rate,N) 
     elif -50 < bal < 50: 
      return N 
     else: 
      return bal 


result=Credit(bal,rate,N) 
print(result) 

我的代碼永遠不會終止。問題是代碼中定義的N值沒有變化。它仍然是固定的N = upper_b + lower_b）/ 2

Answer 1

使用遞歸不是理想的方法，你也有邏輯錯誤，包括需要得到月份的利率，你的初始上限應該大於委託人加上興趣。您可以使用while循環與內部的for循環每個不成功內環復位後的餘額：

balance = int(raw_input("Enter balance")) 
int_rate = float(raw_input("enter rate")) 
int_rate /= 100 
lower_b = balance/12. 
upper_b = ((balance * (1 + (int_rate/12.0)) ** 12)/12.0) 
payment = (lower_b + upper_b)/2 
def Credit(bal, rate, low, high, pay): 
    new_b = bal 
    # calculate monthly interest rate 
    month_int = rate/12 
    while abs(new_b) > 0.001: # use epsilon 
     # always reset balance 
     new_b = bal 
     for _ in range(12): # loop over 12 month range 
      new_b -= pay # deduct pay 
      new_b += month_int * new_b 
     # if we still have a balance we need to take more so set low to current payment 
     if new_b > 0: 
      low = pay 
     # else we took to much so set high to current payment 
     else: 
      high = pay 
     pay = (low + high)/2.0 
    return "Lowest monthly payment over 12 months: {}".format(pay) 


print(Credit(balance, int_rate, lower_b, upper_b, payment))