//-- Scott Munro
//--
import java.util.*;

//create class myArray
class myArray
{

    //two private instance variables (size, len)
    private int size;
    private int len;

    //third instance variable
    private double a[];

    //constructor, takes parameter named size
    myArray(int size)
    {
        this.size = size;

        //allocate array
        a = new double[this.size];
        len = 0;
    }

    //3 methods (display, reset, set)

    void display()
    {
        //traverse array
        for(int i = 0; i < len; i++)
        {
            //print each element of array
            System.out.print("a["+ i + "] = "+ a[i] + " ");
        }
        System.out.println("");
    }

    void reset()
    {
        //traverses array
        for(int i = 0; i < size; i++)
        {
            a[i] = -1;
            len = 0;
        }
    }

    int len()
    {
        return len;
    }

    //adds value to end of array
    boolean add(double value)
    {
        boolean success=false;
        //Return false if array is full
        if(len<size)
        {
            success=true;
            a[len]=value;
            len++;
        }

        return success;
    }

    //adds value to specified location
    boolean add(int element, double value)
    {
        boolean success = false;
        //return false if array is full
        if(len<size)
        {
            success=true;
            //shift items to make room for insert
            for(int i = len; i>element; i--)
                a[i]=a[i-1]; //shift
            a[element] = value;
            len++;
        }

        return success;
    }

    double get(int element)
    {
        double value = -1;

        if (element<len)
        {
            value = a[element];
        }

        return value;
    }

    double set(int element, double value)
    {
        double old = -1;

        if(element<len)
        {
            old = a[element];
            a[element] = value;
        }

        return old;
    }

    double remove(int element)
    {
        int success= -1;

        //check for valid index first
        if(element<len)
        {
            success=0;
            //shift list up starting at remove point
            for(int i = element; i < len-1;i++)
                a[i]=a[i+1];
            len--;
        }
        return success;
    }
}

class Array4
{
    public static void main( String args[])
    {
        Scanner scan = new Scanner (System.in);
        System.out.print("Enter array size: ");
        int size = scan.nextInt();
        String flush = scan.nextLine();

        myArray A = new myArray(size);

        double val;
        int ele;

        //Command interface
        char nChar;
        do
        {
            System.out.println("Choose Command: ");
            System.out.println("<d>isplay, <r>eset,<l>en, <s>et, <a>dd, <i>nsert, r<e>move, <g>et, <q>uit");
            String sCommand = scan.nextLine();
            System.out.println("");
            nChar = sCommand.charAt(0);
            switch (nChar)
            {
                case 'd':
                    A.display();
                    break;

                case 'r':
                    A.reset();
                    break;

                case 's':
                    System.out.print("Enter element: ");
                    ele = scan.nextInt();
                    System.out.print("Enter value: ");
                    val = scan.nextDouble();
                    flush = scan.nextLine();
                    double old = A.set(ele, val);
                    if(old == -1)
                        System.out.println("**SET OPERATION FAILED**");
                    else
                        System.out.println("Previous value was " + old);
                    break;

                case 'e':
                    System.out.print("Enter element: ");
                    ele = scan.nextInt();
                    flush = scan.nextLine();
                    if(A.remove(ele) == -1)
                        System.out.println("**SET OPERATION FAILED**");
                    break;

                case 'l':
                    System.out.println("Length is " + A.len());
                    break;

                case 'a':
                    System.out.print("Enter value: ");
                    val = scan.nextDouble();
                    flush = scan.nextLine();
                    if(!A.add(val))
                        System.out.println("**ADD FAILED**");
                    break;

                case 'i':
                    System.out.print("Enter element: ");
                    ele = scan.nextInt();
                    System.out.print("Enter value: ");
                    val = scan.nextDouble();
                    flush = scan.nextLine();
                    if(!A.add(ele,val))
                        System.out.println("**ADD FAILED**");
                    break;

                case 'g':
                    System.out.print("Enter element: ");
                    ele = scan.nextInt();
                    flush = scan.nextLine();
                    val = A.get(ele);
                    if(val == -1)
                        System.out.println("**INVALID INDEX**");
                    else
                        System.out.println("Get value is "+ val);

                case 'q':
                    break;

                default:
                    System.out.println("**INVALID COMMAND**");
            }
        }
        while(nChar != 'q');
    }
}