Actually, no. Well, not the way you've tried to do it, anyways.
You're going to have to be clearer on a few things.
Firstly, you have defined student's name member as a single char. There aren't many students, regardless of nationality, who's name is a single character. Either make the name an array of char or (better) make the name of type std::string (which represents a set of characters internally). std::string is a type in the standard header named <string>.
Second, it is not possible to just declare member functions in main() and use them - compilers will object. They need to be defined somewhere else. More importantly, non-static member functions can only be used on an instance of the class. They cannot be called standalone. So
Code:
// your definition of the student class
int student::getroll_no() {return roll_no;} // implement the getroll_no() member function
int main()
{
student person;
int number = person.getroll_no(); // this will work: person is an instance of student
student::getroll_no(); // this will not compile as it is not operating on an instance of student
person.student::getroll_no(); // this will also work
}
Mind you, given that your code provides no means to set the name and roll_no methods of a student (for example, a user-defined constructor) there is no point in having the member functions to get their values.