python作业（二）

# print(5 < 4 or 3)   #3
# print(2 > 1 or 6)   #t
# print(3 >1 and 0)   #0
# #计算 1 - 2 + 3 ... + 99 中除了88以外所有数的总和

# i = 1
# sum = 0
# while i < 100:
#     if i != 88:
#         if i % 2 > 0:
#             sum += i
#         else:
#             sum -= i
#     i += 1
# print(sum)

##⽤户登陆（三次输错机会）且每次输错误时显示剩余错误次数（提示：使⽤字符串格式化）
# i = 1
# uname = "jinyu"
# pd = "123456"
# while i < 4:
#     unamei = input("please input name")
#     pdi = input("please inptu pd")
#     if unamei == uname and pdi == pd:
#         print("bingo")
#         break
#     else:
#         print("fales you have %d" %(3 - i))
#     i += 1
# else:print("pppppp")

# #计算 1 - 2 + 3 ... -99 中除了88意外所有数的总和
i = 0
sum = 0
j = -1
while i < 99:
    i += 1
    if i == 88:
        continue
    else:
        j = -j
        sum = sum + i * j
print(sum)