Python基础2：流程控制语句-------条件选择

一，随机输入三个数，并判断最大值

print("这是一个比肩参数最大值的小程序")
number1 = input('请输入参数1：')
number2 = input('请输入参数2: ')
number3 = input('请输入参数3: ')

max_num = 0

if number1 > number2:
    max_num = number1
    if max_num > number3:
        print('最大的数是：'+ max_num)
    else:
        print('最大的数是：'+ number3)
else:
    max_num = number2
    if max_num > number3:
        print('最大的数是：' + max_num)
    else:
        print('最大的数是：' + number3)

 

二，模拟一个帐号登陆程序，错误三次无法登陆并退出程序

A = 1
#初始化密码
password = '123456'
S = True

#开始循环
while S:
    mima = input("请输入密码: ")
    #密码正确，跳出循环
    if password == mima:
        print("密码正确，欢迎登陆")
        S = False
    #循环3次，终止程序
    elif A == 3:
        print("错误次数达到3次，中断登陆")
        break
    #密码错误，继续循环
    else:
        print("密码错误，请重新输入")
    A = A+1
else:
    print("欢迎登陆")

 

 1 user = 'CatdeXin'
 2 passwd = 'abc123'
 3 
 4 counter = 0
 5 while counter < 3:
 6     username = input('username: ')
 7     password = input('password: ')
 8 
 9     if username == user and password == passwd:
10         print("welcome %s login..."% user)
11         passwd_authentication = True
12         break
13     else:
14         print("Invalid username or password !")
15 
16     counter += 1
17     if counter == 3:
18         keep_going_choice = str.title(input("Do you try to start again?【Y/N】"))
19         if keep_going_choice == 'Y':
20             counter = 0
21 
22 else: print("Invalid username or password !")

 

三，输入99乘法表

x = 1

while y < 10:
    #print(str(x)+'*'+str(x)+'=',x*x)
    y = 1
    while y <= x:
        print(y,'*',x,'=',y*x,end="\t")
        y += 1
    print()
    x+=1