python基础一

1.使用while输出1 2 3 4 5 6 ... 10

count = 1
while count <=10 :
    if count == 7:
        print(" ")
    else:print(count)
    count +=1

 2.求1-100的和

count =1
sum = 0
while count <=100 :
    sum += count
    count+=1
print(sum)

3.输出1-100的所有奇数

num=1
while num<=100 :
    if num%2!=0 :
        print(num)
    num+=1

4.求1-2+3-4...99的所有数之和

num = 1
sum = 0
flag=1
while num <= 99:
    sum+=num*flag
    flag=flag * -1
    num+=1
print(sum)

5.用户登录（三次重试机会）假设密码账户均为admin

count = 3
while True :
    user = input("请输入账号")
    password = input("请输入密码")
    if user == "admin" and password == "admin" :
        print("登录成功")
        break
    else:
        count -= 1
        if count!=0:
            print("你还有", count, "次机会")
        else:
            print("登录失败")
            break