1.打印此号码：
1 2 3 4 5 5 4 3 2 1
no = 1
top = 5
direction = 1
while no>0:
print(no,end= ' ')
if no == top:
print(no,end=' ')
direction = -1
no = no + direction
1 2 3 4 5 5 4 3 2 1
2.猜数字游戏：
import random
system_no = random.randint(1,20)
while true:
guess = int(input("enter the no. "))
if guess == system_no:
print("hurray! i got the number!! ")
break
elif guess > system_no:
print("your guess is too high! ")
else:
print("your guess is too low! ")
enter the no. 15 your guess is too low! enter the no. 17 your guess is too low! enter the no. 19 hurray! i got the number!!
3.找出数字中最大的数字
no = int(input("enter no. "))
max_no = 0
while no>0:
rem = no%10
if rem>max_no:
max_no = rem
no//=10
print(max_no)
enter no. 2357 7
4.找出数字中最小的数字
no = int(input("enter no. "))
min_no = 9
while no>0:
rem = no%10
if rem
enter no. 2357
2
5.collatz 序列
编写一个程序，打印给定数字的 collatz 序列，直到达到 1。
规则：
if the number is even: n=n/2
if the number is odd: n=3n+1.
def even_odd(no):
while no>0:
num=no%10
if num%2==0:
even=num/2
else:
odd=3*num+1
no=no//10
return even,odd
no=int(input("enter the number:"))
even,odd=even_odd(no)
print("even number:",even)
print("odd number:",odd)
Enter the number:12
even number: 1.0
odd number: 4
