Write a program that lets you know if you can have a key or not, based on your role at the school.
First ask for the user’s role at the school. They can be a student, administrator, or a teacher. (And remember that capitalization is important! ‘Student’ is not the same as ‘student’.)
Example 1: Administrator or Teacher
For example, if this was the input:
Are you an administrator, teacher, or student?: teacher
This should be the output:
Administrators and teachers get keys!
Example 2: Student
And if this was the input:
Are you an administrator, teacher, or student?: student
This should be the output:
Students do not get keys!
(Note: You should also be able to handle a situation where the user enters a value other than administrator, teacher or student and tell them they must be one of the three choices!)
Example 3: Other
If they input anything else:
Are you an administrator, teacher, or student?: secretary
This should be the output:
You can only be an administrator, teacher, or student!
Ответ:
255.255.252.0
Объяснение:
1022 абонента. Плюс один нулевой, итого 1023
В двоичной системе будет
00000000 00000000 00000011 11111111
Инвертируем и получаем
11111111 11111111 11111100 00000000
Переводим каждый байт в десятичное число
255 255 252 0
Расставляем точки в нужных местах
255.255.252.0
Ответ:
1022 абонента, ближайшее число — степень двойки это 1024, что является 2^10 степени, нам нужна маска с 10 нулями и 22 единицами соответственно, ищем маску с префиксом 22 >> 255.255.252.000
Предпоследнее число: 252