day1我学会了什么？

   以前都是自己自学python没有老师的讲解没有同学们一起学习的氛围，自己的进展很慢。

通过第一天认真的听讲，使我对基础部分记忆的更加的深刻了。

作业：

求一百以内的和：

# -*- coding:utf-8 -*-
sum = 0

count = 1
while count < 101:
    sum = sum + count
    count = count + 1
print(sum)
一百以内的奇数：

# -*- coding:utf-8 -*-
count = 0
while True:
    if count == 100:
        break
    count = count + 1
    if 0 != count % 2:
        print(count)
一百以内的偶数：

# -*- coding:utf-8 -*-
count = 1
while count < 101:
    div = count % 2
    if div == 0:
        print(count)
    else:
        pass
    count = count + 1
求1-2+3-4+5 ... 99的所有数的和：

# -*- coding:utf-8 -*-
count = 1
sum = 0
while count < 100:
    div = count % 2
    if div == 1:
        sum = sum + count
    else:
        sum = sum - count
    count = count + 1
print(sum)
用户登录（三次错误机会）：

# -*- coding:utf-8 -*-
counts = 0
user_list =  [{'username':'jack', 'password':'123456' },{'username':'tom', 'password':'123456'},
              {'username':'jieru', 'password':'123456'},{'username':'xiaogang', 'password':'123456'},]

flag = False
for item in user_list:
    user = input("请输入用户名：")
    passwd = input("请输入密码：")
    if item['username'] == user and item['password'] == passwd:
        flag = True
        print("登录成功")
        break
    else:
        print("登录失败")
        counts = counts + 1
    if counts == 3:
        print("您已经输错三次，不能再输入了。")
        break