redesign the grading program as an object-oriented design. We will start with a simple Student class. The student will have a name, an id (as a String) and a set of grades (as doubles).
The Student class should include:
* a constructor (which takes a name and id as strings),
* getters and setters for the name and id,
* addGrade method : void
  *which takes a double,
*printGrades method : void
*which prints the name, a colon, and the grades separated by commas,
* getAdjustedAverage method : double
* computes the average, dropping the lowest score
*getLetterGrade method : char
* compute the letter grade based on the adjusted average and a straight scale
* toString() method : String
* prints the "():"