Create a class called Student that models a student. A student's state consists of a name (string), id number (int) and a list of grades (array of doubles). Include a constructor that has three input parameters (name, id and grade list) and sets the initial state for the object.

Write a toString method that returns a useful string representation of a student object. The string representation should contain the student's name and ID number (in some readable format). Write a getAverage method that returns the average grade (a double) for the student object if they have 1 or more grades and returns -1.0 if they do not.