求100以内的偶数

1、

num = 1
while num<=100:
    if num%2 ==0:
        print(num)
    num += 1

2、

for num in range(1,101):
    if num % 2 == 0:
        print(num)

3、

for num in range(0,101,2)
    print(num)

 

while 无限循环

for 有限循环