private bool studentExists(int id)
{
/*
* pre cond: int id
* post cond: true - if student id is found in stack
* false - otherwise
*
* checks if a student id was already used
*/
Student student;
Stack newStack = new Stack(this.repo.getStackCapacity());
bool ok = false;
while (!ok && this.repo.getStackSize() > -1)
{
student = this.repo.getStudent();
if (student.getId() == id)
ok = true;
newStack.push(student);
}
while (newStack.getStackSize() > -1)
this.repo.addStudent(newStack.pop());
if (ok) return true;
else return false;
}
public String deleteStudentsUntilGrade(int grade)
{
/*
* pre cond: int grade (the limit grade)
* post cond: specific string
*
* deletes all students until 'grade' is found
*/
try
{
Stack newStack = new Stack(this.repo.getStackCapacity());
Student student;
while (this.repo.getStackSize() > -1)
{
student = this.repo.getStudent();
if (student.getGrade() == 10)
{
this.repo.addStudent(student);
return "Students deleted successfully!";
}
newStack.push(student);
}
return "No students with the grade 10 found; all students have been deleted!";
}
catch (StudentException ex)
{
return ex.getMessage();
}
}
public String getAllStudents()
{
/*
* pre cond: -
* post cond: a string with all the students
* or a message if no students have been added
*
*/
String studentList = "";
Student student;
if (repo.getStackSize() < 0)
return "No students!";
Stack newStack = new Stack(this.repo.getStackCapacity());
while (this.repo.getStackSize() > -1)
{
student = this.repo.getStudent();
studentList += student.toString() + "\n";
newStack.push(student);
}
while (newStack.getStackSize() > -1)
this.repo.addStudent(newStack.pop());
return studentList;
}
public StudentRepository(int capacity)
{
this.capacity = capacity;
this.stack = new Stack(capacity);
}