【发布时间】：2011-03-18 04:55:09
【问题描述】：
背景：
在我的计算机科学课上，我们被要求创建一个程序来帮助小学生学习基础数学。
他们会选择他们想学习的操作（加法、减法、乘法或除法），或者选择随机的，这将随机选择其中一种操作。
一旦选择了一个操作，用户将被问一个问题，然后输入答案，如果正确，程序会再问一个问题，总共最多 4 个问题，然后程序将返回菜单。
如果答案不正确，它会要求用户重新输入答案，最多3次，如果答案仍然不正确，将显示正确答案，然后再问一个问题（如果没有达到4个问题配额) 或在没有其他问题时返回菜单。
问题：
我把所有的东西都写出来了，当我在 IDLE 中运行程序时，一切似乎都在工作，但由于某种原因选择了一个操作后，程序卡在无限循环中，并且在问了 4 个问题后不会返回菜单。
我首先使用了一个 for 循环来满足 4 个问题的配额，但它不起作用，所以我尝试了一个读取 while x<4: etc etc 的 while 循环，在 while 循环之前将 x 定义为 x=0，然后在函数末尾添加x=x+1.
再次通过阅读代码，它似乎应该适用于每个函数，但在运行它之后我仍然陷入无限循环。
代码如下：
def show_instructions():
"""
Displays a greeting to the user and provides instructions on how to use the
program. [PURPOSE]
"""
print " "
print "-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-"
print " Math Mania"
print " "
print "Welcome to Math Mania! This program is designed to help you learn basic"
print "math skills in addition, subtraction, multiplication, and division."
print "-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-"
print " "
print "To learn a skill, type the first letter of that skill."
print " "
print "a for addition"
print "s for subtraction"
print "m for multiplication"
print "d for division"
print "r for random"
print "q to quit"
print " "
def add():
"""
generates display two random numbers and sums them, then prompts the user
to input the correct sum, if the input is incorrect, it prompts the user
to try again.
[PURPOSE]
"""
x=0
while x<4:
num1 = random.randint(1,20)
num2 = random.randint(1,20)
print num1, "+", num2, '= ?'
answer = input ('Enter your answer: ')
count1=0
while answer != num1+num2 and count1<3:
count1=count1 +1
print 'Incorrect, please try again.'
print
print num1, '+', num2, '= ?'
answer = input ('Enter your answer: ')
if count1==3:
print "Sorry, that's incorrect."
print "The correct answer is ",num1+num2
else:
print "That's correct!"
print
x=x+1
def sub():
"""
generates and displays two random numbers and subtracts the smaller of the
two from the larger one. It then prompts the user to input the correct
answer, if the input is incorrect, it prompts the user to try again.
[PURPOSE]
"""
x=0
while x<4:
num1 = random.randint(1,20)
num2 = random.randint(1,20)
if num1>num2:
print num1, "-", num2, '= ?'
answer = input('Enter your answer: ')
count1=0
while answer != num1 - num2 and count1<3:
count1=count1+1
print 'Incorrect, please try again.'
print
print num1, "-", num2, '= ?'
answer = input ('Enter your answer: ')
if count1==3:
print "Sorry, that's incorrect."
print "The correct answer is ",num1-num2
else:
print "That's correct!"
print
x=x+1
else:
print num2, "-", num1, '= ?'
answer = input ('Enter your answer')
count1=0
while answer!= num2-num1 and count1<3:
count1=count1+1
print 'Incorrect, please try again.'
print
print num2, "-", num1, '= ?'
answer = input ('Enter your answer: ')
if count1==3:
print "Sorry, that's incorrect."
print "The correct answer is ",num2-num1
else:
print 'Thats correct!'
print
x=x+1
def mult():
"""
generates and displays two random numbers and finds the product of the two.
It then prompts the user to input the correct product of the two numbers, if
the input is incorrect, it prompts the user to try again.
[PURPOSE]
"""
x=0
while x<4:
num1 = random.randint(1,20)
num2 = random.randint(1,20)
print num1, "x", num2, '= ?'
answer = input ('Enter your answer: ')
count1=0
while answer != num1*num2 and count1<3:
count1=count1+1
print 'Incorrect, please try again.'
print
print num1, 'x', num2, '= ?'
answer = input ('Enter your answer: ')
if count1==3:
print "Sorry, that's incorrect."
print "The correct answer is ", num1*num2
else:
print "That's correct!"
print
x=x+1
def div():
"""
generates and displays the quotient of two numbers, and then prompts the
user to input the correct answer, if the input is incorrect, it then prompts
the user to try again.
[PURPOSE]
"""
x=0
while x<4:
num1 = random.randint(1,20)
num2 = random.randint(1,20)
while (num1%num2!=0):
num2 = random.randint(1,20)
num1 = random.randint(1,20)
print num1, "/", num2, '= ?'
answer = input ('Enter your answer: ')
count1=0
while answer != num1/num2 and count1<3:
count1=count1 +1
print 'Incorrect, please try again.'
print num1, '/', num2, '= ?'
answer = input ('enter your answer:')
if count1==3:
print "Sorry, that's incorrect."
print "The correct answer is ",num1/num2
else:
print "That's correct!"
print
x=x+1
def rand():
"""
picks a arithmetic function at random for the user to to try
[PURPOSE]
"""
num=random.randint(1,4)
if num==1:
add()
if num==2:
sub()
if num==3:
mult()
if num==4:
div()
def main():
"""
main function that brings it all together
[PURPOSE]
"""
show_instructions()
selection = raw_input ('Please select the skill you want to learn: ')
while selection != "q":
if selection == "a":
add()
elif selection == "s":
sub()
elif selection == "m":
mult()
elif selection == "d":
div()
elif selection == "r":
rand()
print "The program will now quit."
quit()
main()`
提前感谢您在这里提供的任何帮助！
【问题讨论】：
-
请原谅我问题中代码的格式，我是该网站的新手，不知道如何在我的问题中正确显示我的代码
-
在编辑器中输入代码块后，突出显示它并单击
{}按钮。所做的只是缩进整个块 4 个空格。 -
谢谢吉姆，下次我使用这个网站时一定要记住这一点！
标签： python debugging loops infinite