"How do I separate the student from the ID from the grade using getline?"
Go back to the beginning of the thread and read all the posts. Take notes and study what each post has to say. You might even want to print them all out. All the information you need to complete your program is in the posts.
student\student.h(16) : error C2062: type 'void' unexpected
A function with a void return type can't have
That return statement returns an int.
istudent\student.cpp(11) : error C2039: 'GetGrade' : is not a member of 'Student'
See anything wrong with that function declaration?
I suggest you begin your C++ studies over. Start with a "Hello World" program and get a good C++ book like "Ivor Horton's Beginning C++". If you can't catch errors like missing semicolons at the end of a line, and you don't know about return types, you aren't going to be successful programming with classes. Sorry, but your in way over your head with this program.
Please help me with the error above...(vector.h is not my program)