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