python基础二

1.计算 1 - 2 + 3 ...99中除了88以外所有数的总和

sum = 0
count = 1
flag = -1
while count <= 99:
    flag *= -1
    if count == 88:
        count += 1
        continue
    sum = sum + count * flag
    count += 1
print(sum)

2.用户登录（三次重试机会）假设密码账户均为admin（完善版）

count = 3
while True :
    user = input("请输入账号")
    password = input("请输入密码")
    if user == "admin" and password == "admin" :
        msg = '''恭喜您登录成功
        用户名：%s
        密  码：%s
        '''%(user,password)
        print(msg)
        break
    else:
        count -= 1
        if count!=0:
            print("你还有", count, "次机会")
            flag = input("是否继续输入y/n")
            if flag != 'y':
                print("登录失败")
                break
            else :print("请继续输入")
        else:
            print("登录失败")
            print("机会已经用完，下次见")
            break