我刚开始编程大约一周前，这对我来说仍然有点新鲜。 每当我介绍一个有效的字母：B，D或W时，程序就会起作用，如果那时我会引入一个不正确的字母，它会要求输入另一个字母，如果我把B，D，W或Q放入，它会再次起作用。 但是，如果我首先引入一个不正确的值，比如Z，然后我给它一个B，那么它将不起作用，它会说它仍然不正确。
提前谢谢!!
#This program will calculate the amount due of a customer after they
#rent a car and they input all the data that is asked.
#The import math is for math.ceil, used to round up the days to weeks.
import math
user_input = input ('Enter classification code1: ')
correct_code = user_input == 'B' or user_input == 'D' or user_input == 'W'
while (user_input != 'Q') and (user_input != 'q'):
print ('Customer code:', user_input, '\n')
if correct_code :
#Here starts the first case. Code W:
if user_input == 'B':
print ('Your classification code is: ', user_input)
days = int ( input ('Number of days: '))
odometer_start = int ( input ('Odometer reading at the start: '))
odometer_end = int ( input ('Odometer reading at the end: '))
#These are the calculations in case the odometer surpasses the limit (999999)
if (odometer_start <= 999999 and odometer_start >= 900000) and (odometer_end >= 0 and odometer_end <= 100000) :
odometer_end += 1000000
else :
odometer_end += 0
#These are the calculations for the amount of miles driven and the amount due
miles_driven_str = (odometer_end - odometer_start) / 10
miles_driven = float (miles_driven_str)
amount_due_str = (40.00 * days) + (0.25 * miles_driven)
amount_due = float (amount_due_str)
#this is what the customer will see an now will be able to input their data
print ('\n')
print ('Customer summary: ', '\n')
print ('\t', 'Classification code: B')
print ('\t', 'Rental period (days): ', days)
print ('\t', 'Odometer reading at start :', odometer_start)
print ('\t', 'Odometer reading at end :', odometer_end)
print ('\t', 'Number of miles driven :', round (miles_driven,1))
print ('\t', 'Amount due: $', round (amount_due,2))
print ('\n')
#This is the second case. Code D:
elif user_input == 'D' :
print ('Your classification code is: ', user_input)
days = int ( input ('Number of days: '))
odometer_start = int ( input ('Odometer reading at the start: '))
odometer_end = int ( input ('Odometer reading at the end: '))
#These are the calculations in case the odometer surpasses the limit (999999)
if (odometer_start <= 999999 and odometer_start >= 900000) and (odometer_end >= 0 and odometer_end <= 100000) :
odometer_end += 1000000
else :
odometer_end += 0
#These are the calculations for the amount of miles driven and the basic amount
#that is due (without calculating the extra miles)
miles_driven_str = (odometer_end - odometer_start) / 10
miles_driven = float (miles_driven_str)
amount_due_str = (60.00 * days)
amount_due = float (amount_due_str)
#These are the calculations for the amount to be added to the basic amount due
#This will add the cost of the extra miles if the customer has travelled more
#miles that the permitted.
if miles_driven > 100 :
extra_miles = miles_driven - 100
else :
extra_miles = 0
amount_due_extra = amount_due + (0.25 * extra_miles)
#this is what the customer will see an now will be able to input their data
print ('\n')
print ('Customer summary: ', '\n')
print ('\t', 'Classification code: D')
print ('\t', 'Rental period (days): ', days)
print ('\t', 'Odometer reading at start :', odometer_start)
print ('\t', 'Odometer reading at end :', odometer_end)
print ('\t', 'Number of miles driven :', round (miles_driven,1))
print ('\t', 'Amount due: $', round (amount_due_extra,2))
print ('\n')
elif user_input == 'W' :
print ('Your classification code is: ', user_input)
days = int ( input ('Number of days: '))
odometer_start = int ( input ('Odometer reading at the start: '))
odometer_end = int ( input ('Odometer reading at the end: '))
#These are the calculations in case the odometer surpasses the limit (999999)
if (odometer_start <= 999999 and odometer_start >= 900000) and (odometer_end >= 0 and odometer_end <= 100000) :
odometer_end += 1000000
else :
odometer_end +=0
#These are the calculations for the amount of miles driven and the basic amount
#that is due (without calculating the extra miles)
weeks_rented = math.ceil (days / 7)
miles_driven_str = (odometer_end - odometer_start) / 10
miles_driven = float (miles_driven_str)
amount_due_str = (190.00 * weeks_rented)
amount_due = float (amount_due_str)
#These are the calculations for the amount to be added to the basic amount due
#This will add the cost of the extra miles if the customer has travelled more
#miles that the permitted.
if miles_driven > (900 * weeks_rented) and miles_driven < (1500 * weeks_rented) :
amount_due_extra = amount_due + 100.00
elif miles_driven > (1500 * weeks_rented) :
extra_miles = miles_driven - (1500 * weeks_rented)
amount_due_extra = (amount_due + (200.00 * weeks_rented)) + ( 0.25 * extra_miles )
else :
amount_due_extra = amount_due + 0
#this is what the customer will see an now will be able to input their data
print ('\n')
print ('Customer summary: ', '\n')
print ('\t', 'Classification code: W')
print ('\t', 'Rental period (days): ', days)
print ('\t', 'Odometer reading at start :', odometer_start)
print ('\t', 'Odometer reading at end :', odometer_end)
print ('\t', 'Number of miles driven :', round (miles_driven,1))
print ('\t', 'Amount due: $', round (amount_due_extra,2))
print ('\n')
#This is for when the input is not: B, D, or W.
else :
False
print ('Incorrect classification code.')
#This is for when the input is not: B, D, or W.
else:
print ('Incorrect classification code. Try again')
user_input = input ('Enter classification code: ')
print ('\n')
print ('Done.')
答案 0 :(得分：3)
您需要移动此行
correct_code = user_input == 'B' or user_input == 'D' or user_input == 'W'
while循环中，以便在您检查之前每次都重新计算correct_code的值。就目前而言，correct_code仅在第一次输入后计算一次。