不用中间变量交换a和b的值？

a =
b = 

a = a+b
b = a-b
a = a-b
print(a,b)

a =
b = 

a = a^b
b = b^a
a = a^b
print(a,b)

a =
b = 

a,b = b,a
print(a,b)

输出

(, )
(, )
(, )