一段Python代码自动出20以内的加减算术题

# -*- coding=utf-8 -*-


import sys
import random
import time


sys.setrecursionlimit(100)




def randint():
    return random.randint(0,20)


def get_add_result(x,y):
    if x + y <= 20 :
        print ('%2d + %2d = ? ' % (x, y))
        time.sleep(3)
        print ('答案是:')
        return ('%2d + %2d = %2d ' %(x,y,x+y))
    else:
        return get_add_result(randint(),randint())


def get_sub_result(x,y):
    if x-y > 0:
        print ('%2d - %2d = ? ' % (x, y))
        time.sleep(3)
        print ('答案是:')
        return ('%2d - %2d = %2d ' %(x,y,x-y))
    else:
        return get_sub_result(randint(),randint())
def get_calc_type():
    calc_type = random.randint(0,1)
    if calc_type == 0:
        return get_add_result(randint(),randint())
    else:
        return get_sub_result(randint(), randint())


def get_result():
    for i in range(20):
        print ('请看第%s题:' %(i+1))


        print (get_calc_type())
        time.sleep(3)


if __name__ == '__main__':
    get_result()