python学习day 9课后习题

count = 0
while count < 11:
    print(count)
    count += 1

求1-100内的和

count = 0
sum = 0
while count < 101:
    sum = sum +count
    count += 1
print(sum)

输出1到100的奇数

count = 0
while count < 101:
    if count % 2 == 1:
        print(count)
    count += 1
输出1到100所有偶数

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

求1-2+3—4....99所有数的和

count = 0

sum = 0
while count < 100:
    if count % 2 == 1:
        sum = sum + count
    else:
        sum = sum - count
    count += 1
print(sum)

用户登录，三次机会重试

i = 0
while i < 3:
    a = input("请输出密码：")
    if a == "123":
        print("输入正确")
        break
    else:
        print("输入错误请重新输入")
        i += 1
if a == "123":
    print("登录成功")
else:
    print("您已输入三次，账户已锁定")