public void parameters()
{
Student2 student = new Student2();
// call by value
double simpleGrade = 3.2;
student.modifyGrade(simpleGrade);
Assert.assertThat("simpleGrade should still be the same", simpleGrade == 3.2);
student.modifyGrade(ref simpleGrade);
Assert.assertThat("simpleGrade has now changed",simpleGrade == 0.0);
Grade grade = new Grade(1.3, "programming");
DateTime dateTimeBefore = grade.Date;
student.addGrade(grade);
Assert.assertThat("the date in grade has changed", grade.Date != dateTimeBefore);
}
public void addGrade(Grade grade)
{
grade.Date = DateTime.Now;
}