Stack

stack_IMyStack.java

package week5.main.stack;

/**
 * Created by sasha on 09.08.2016.
 */
public interface IMyStack<E> {

    void  push(E element);

    E pop();

    E peek();

    Integer stackSize();


    String toString ();
}

stack_MyArrayStack.java

package week5.main.stack;

/**
 * Created by sasha on 09.08.2016.
 */
public class MyArrayStack<E> implements IMyStack<E> {

    private final int DEFAULT_CAPACITY = 5;
    private int top;
    private E[] arrayStack;

    public MyArrayStack(){
        top = 0;
        arrayStack = (E[])(new Object[DEFAULT_CAPACITY]);
    }

    public MyArrayStack(int startCapacity){
        top = 0;
        arrayStack = (E[])(new Object[startCapacity]);
    }

    private void expansCapacity(){
        E[] largStack = (E[])(new Object[stackSize() * 2]);
        System.arraycopy(arrayStack, 0, largStack, 0, stackSize());
        arrayStack = largStack;
    }

    private boolean isEmpty(){
        return top == 0;
    }

    private boolean isFull(){
        return arrayStack.length == stackSize();
    }

    @Override
    public void push(E element) {
        if (isFull()){
            expansCapacity();
        }
        arrayStack[top] = element; //Yanchevskaya A перепиши в одну строку
        top++;
    }

    @Override
    public E pop() {
        E result = null;
        if (!isEmpty()){
            result = arrayStack[top - 1];
            arrayStack[top - 1] = null; //Yanchevskaya A перепиши в одну строку
            top--;
        }else {
            System.out.println("stack is empty");
        }
        return result;
    }

    @Override
    public E peek() {
        E result = null;
        if (!isEmpty()){
            result = arrayStack[top - 1];
            } else {
            System.out.println("stack is empty or index outside of stack");
        }
        return result;
    }

    @Override
    public Integer stackSize() {
        return top;
    }

    @Override
    public String toString() {
        String str = ""; //Yanchevskaya A use StringBuilder
        for (int i = top - 1; i >= 0; i--){
            str+=String.valueOf(arrayStack[i]) + "\t";
        }
        return str;
    }
}

stack_MyLinkedStack.java

package week5.main.stack;

/**
 * Created by Agryzkov on 10.08.2016.
 */
public class MyLinkedStack<E> implements IMyStack<E> {

    private int capasity;
    private Node<E> top;

    public MyLinkedStack() {
        top = null;
        capasity = 0;
    }

    private boolean isEmpty() {
        return capasity == 0;
    }

    @Override
    public void push(E element) {
        Node<E> stack = new Node<E>(element);
        stack.setNext(top);
        top = stack;
        capasity++;
    }

    @Override
    public E pop() {
        E result = null;
        if (isEmpty()) {
            System.out.println("stack is empty");
        } else {
            result = top.getValue();
            top = top.getNext();
            capasity--;
        }
        return result;
    }

    @Override
    public E peek() {
        E result = null;
        if (isEmpty()) {
            System.out.println("stack is empty");
        } else {
            result = top.getValue();
        }
        return result;
    }

    @Override
    public Integer stackSize() {
        return capasity;
    }

    @Override
    public String toString(){
        String result = ""; //Yanchevskaya A use StringBuilder
        Node<E> current = top;

        while (current != null){
            result += String.valueOf(current.getValue()) + "\t";
            current = current.getNext();
        }
        return result;
    }
}

stack_Node.java

package week5.main.stack;

/**
 * Created by sasha on 10.08.2016.
 */
public class Node<E> {

    private E value;
    private Node<E> next;

    public Node(){};

    public Node(E value) {
        this.value = value;
    }

    public E getValue() {return value;}

    public void setNext(Node<E> next) { this.next = next; }

    public Node<E> getNext() { return  next; }




}