【python】实例-答题系统

#!/usr/bin/env pythonfrom operator import add, sub
from random import randint, choiceops = {'+': add, '-': sub}
MAXTRIES = 2def doprob():
op = choice('+-')
nums = [ randint(1,10) for i in range(2) ]
nums.sort(reverse=True)
ans = ops[op](*nums)
pr = '%d %s %s = ' % (nums[0], op, nums[1])
oops = 0
while True:
try:
if int(raw_input(pr)) == ans:##只有正确作答才跳出循环
print 'correct'
break
if oops == MAXTRIES:##第二次给出正确答案，但是依然是这道题目
print 'sorry... the answer is\n%s%d' % (pr, ans)
else:
print 'incorrect... try again'
oops += 1
except (KeyboardInterrupt,
EOFError, ValueError):
print 'invalid input... try again'def main():
while True:
doprob()
try:
opt = raw_input('Again? [y] ').lower()
if opt and opt[0] == 'n':
break
except (KeyboardInterrupt, EOFError):
breakif __name__ == '__main__':
main()