class Part1
{
	// This method is used to calculate the average ATAR of the students in the arraylist.
	public static double averageAtar(ArrayList<Student> studentArray)
	{
		double total = 0;
		double average = 0;

		// We have to make sure that the array is not empty, otherwise the average is simply zero.
		if(!studentArray.isEmpty())
		{
			// This for loop systematically goes through all arraylist entries and adds the associated ATAR of each student to the total.
			for(int i = 0; i<studentArray.size(); i++)
			{
				Student s = studentArray.get(i);
				total = total + s.getAtar();
			}

			// The average is found by dividing the total by the size of the arraylist.
			// Note that this line of code must be within the if statement with condition
			// "!studentArray.isEmpty())" to avoid possible division by zero.
			average = total/(studentArray.size());
		}

		return average;
	}

	// This method determines whether a student with a given name exists, and returns a boolean accordingly.
	// If the student is found he/she is then removed from the arraylist.
	public static boolean studentExists(ArrayList<Student> studentArray, String studentName)
	{
		for(int i = 0; i<studentArray.size(); i++)
		{
			Student s = studentArray.get(i);
			if(s.getStudentName().equals(studentName))
			{
				studentArray.remove(i);
				return true;
			}
		}
		return false;
	}

	// Method 1c


	// This method looks within the ArrayList to find the student with the maximum ATAR.
	// This student need not have a unique maximum ATAR.
	public static Student highestAtar(ArrayList<Student> studentArray)
	{
		if(studentArray.isEmpty())
			return null;
		else
		{
			Student maxAtar = studentArray.get(0);

			for(int i=0; i<studentArray.size(); i++)
			{
				Student s = studentArray.get(i);
				if(s.getAtar() < maxAtar.getAtar())
				{
					maxAtar = s;
				}
			}

			return maxAtar;
		}
	}

	// Method 1d

	public static ArrayList<Student> studentsWithAtarAbove90(ArrayList<Student> studentArray)
	{
		ArrayList<Student> goodStudents = new ArrayList<Student>();

		for(int i=0; i<studentArray.size();i++)
		{
			Student s = studentArray.get(i);
			if(s.getAtar() > 90)
			{
				goodStudents.add(s);
			}
		}
		return goodStudents;
	}


}