迭代器斐波那契数列

class Num:
    total1 = 0

    def __init__(self, num, num1):
        self.num = num
        self.num1 = num1

    def __iter__(self):
        return self

    def __next__(self):
        if self.num>100:
            raise StopIteration('终止了')
        self.num,self.num1 = self.num1,self.num+self.num1
        return self.num
n1 = Num(1,2)
# for i in n1:
#     print(i)
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
print(n1.__next__())
输出：
2
3
5
8
13
21
34
55
89
144
Traceback (most recent call last):
  File "C:/Users/Administrator/Desktop/python/3月9日/斐波那契数列.py", line 29, in <module>
    print(n1.__next__())
  File "C:/Users/Administrator/Desktop/python/3月9日/斐波那契数列.py", line 13, in __next__
    raise StopIteration('终止了')
StopIteration: 终止了

斐波那契数列   可以用交换元素直接进行处理   a,b = b,a+b