import uwcse.io.*;

/**
 * A class to illustrate the concept of dynamic allocation.<br>
 * The class methods allow the user to input an unknown number of grades
 * (between 0 and 100). Internally the grades are stored in array that grows
 * in size as more grades are entered.
 */

public class DynamicAllocation {

    /**
     * Input an unknown number of grades (store them in an array that
     * grows in size as more grades are entered).
     */
    public void inputGrades()
    {
        // Define the array (empty initially)
        int[] grades = new int[0];

        // Read the grades in a loop
        // Store each grade in the array grades
        int grade;
        Input input = new Input();
        do
        {
            grade =  input.readInt("Enter the grade (<0 to quit): ");
            if (grade>=0 && grade<=100)
            {
                // increase the size of the array
                // Use the method increaseSizeByOne
                grades = copyAndIncreaseSizeByOne(grades);
                // store the new grade
                grades[grades.length-1]=grade;
            }
        }
        while(grade>=0);

        // Display all of the grades
        for(int i=0; i<grades.length; i++)
            System.out.println("grade "+i+" is "+grades[i]);
    }

    /**
     * Return an array that contains a copy of the array sent and that
     * is one element bigger than the array sent.
     * @param a the array to copy
     */
    private int[] copyAndIncreaseSizeByOne(int[] a)
    {
        // copy a in array which is one element bigger.
        int[] temp = new int[a.length+1];
        for(int i=0; i<a.length; i++)
          temp[i]=a[i];

        a = temp;
        return a;
    }
}