python22期第一天(作业)

1.求1-100的所有数的和

sum = 0
for i in range(101):
    sum = sum + i

print(sum)

2.1-100内的基数

m = 0
while m < 101:
    i = m%2
    if i == 1:
        print(m)
    m += 1

3.1 - 100以内的偶数

m = 0
while m < 101:
    i = m%2
    if i == 0:
        print(m)
    m += 1

4. 求1-2+3-4+5 ... 99的所有数的和

n = 0
m = 0
while [1]:
     if 0 == n % 2:
         m = m - n
     else:
         m = m + n
     if n == 100:
         break
     n += 1

print(m)

5. 用户登录（三次错误机会）

import sys
user_list = [
    {'username': 'alex', 'password': '123'},
    {'username': 'eric', 'password': '123'},
    {'username': 'tony', 'password': '123'},
    {'username': 'oldboy', 'password': '123'},
]

flag = False
count = 0
while True:
    user = input("请输入用户名：")
    pwd = input("请输入密码：")


    for item in user_list:
            if item['username'] == user and item['password'] == pwd:
                flag = True
            else:
                pass
    if flag:
        print("登录成功")
        exit()
    else:
        print("登录失败,请重新登录")
        count += 1
        if count == 3:
            print('您输入的用户密码错误超过3次,已经退出')
            exit()