4.关于while循环的基础小练习

1）使用while、if循环输入123456 8910

count = 0
while count < 10:
    count += 1
    if count == 7:
        print('')
    else:
        print(count)

　或　

count = 0
while count < 10:
    count += 1
    if count == 7:
        continue
    print(count)

2)输出 1-100 内的所有奇数

1)

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

2)

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

3）求1-2+3-4+5 ... 99的所有数的和

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

4).用户登陆（三次机会重试）

#input 心中有账号，密码 while

 i = 0
 while i < 3:
     username = input('请输入账号：')
     password = int(input('请输入密码：'))
     if username == '咸鱼哥' and password == 123:
         print('登录成功')
     else:
         print('登录失败请重新登录')
     i += 1

5).计算 1 - 2 + 3 ... -99 中除了88意外所有数的总和

i = 0                      #把减号当成符号来运算，例：-2为一个数字  i更改的只是符号
j = -1                     #则 i 为一加一减   sum = i + i *j (sum为i相加）
sum = 0
while i < 99:
    i += 1
    if 1 = 88:
        continue
    else:
        j = -j
    sum = i + i * j
print(sum)