package vector;

import java.util.EmptyStackException;
import org.omg.CORBA.BAD_PARAM;

public class vector {
    private int _size;
    private Object _Array[];

    public vector (int size, Object value) { //fill constructor
        if (size > 0) {
            _size = size;
        }
        else {
            _size = 0;
        }
        _Array = new Object[2*size + 1];
        for (int i = 0; i < _size; ++i)
            _Array[i] = value;
    }

    public vector () {
        this (0, 0);
    }

    public int size () {
        return _size;
    }

    public int capacity () {
        return _Array.length;
    }

    public boolean empty () {
        return (_size == 0);
    }

    public void reserve (int capacity) {
        if (capacity <= 0)
            throw new BAD_PARAM();

        Object Temp_array[] = new Object[capacity];
        for (int i = 0; i < _size; ++i)
            Temp_array[i] = _Array[i];

        _Array = Temp_array;
    }

    public void resize (int size, Object value) {
        if (size < _size && size >= 0) { // change _capacity?
            _size = size;
            return;
        }

        if (size > _size) {
            if (size >= _Array.length) {
                if (2*_Array.length > size)
                    reserve (2*_Array.length);
                else
                    reserve (size);
            }

            for (int i = _size; i < size; ++i)
                _Array[i] = value;

            _size = size;
        }
    }

    public void pushBack (Object value) {
        resize (_size + 1, value);
    }


    public void shrinkToFit () {
        if (_size != _Array.length) {
            Object Temp_array[] = new Object[_size];
            for (int i = 0; i < _size; ++i)
                Temp_array[i] = _Array[i];

            _Array = Temp_array;
        }
    }

    public Object popBack () {
        if (!empty())
            return _Array[--_size];

        throw new EmptyStackException();
    }

    public void clear () {
        _size = 0;
        Object Temp_array[] = new Object[10];
        _Array = Temp_array;
    }

    public Object at (int id) { // ?
        if (id >= _size || id < 0)
            throw new ArrayIndexOutOfBoundsException(id);

        return _Array[id];
    }

    public Object front () {
        return at(0);
    }

    public Object back () {
        return at(_size - 1);
    }
}