[НП] лаб6.1 Генерички магацин (Stack)

/*Генерички податочни структури (6)

Генерички магацин (Stack) Problem 1 (0 / 0)

Да се имплементира генеричката податочна структура магацин (stack). Магацинот има еден генерички параметар T и
следниве методи:

Stack() - креира нов празен магацин
push(T element) - го додава елементот на врвот на магацинот
peek():T - го враќа елементот на врвот на магацинот, но не го отстранува
pop():T - го отстранува и го враќа елементот на врвот на магацинот
isEmpty():boolean - враќа true ако магацинот е празен (не содржи ниту еден елемент)
Може да користите поврзана листа ,единечна или двојна Node<T> или обична низа T[]. Не смеете да користите ArrayList,
LinkedList или некоја друга готова структура. Методите pop и peek треба да фрлат исклучок EmptyStackException доколку
магацинот е празен

Sample input
0 10

Sample output
Test#0
testing: Stack::push(T) , Stack::pop():T , T is Integer
Pushing elements:
1 2 3 4 5 6 7 8 9 10
Poping elements:
10 9 8 7 6 5 4 3 2 1
 */


import java.util.Date;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.EmptyStackException;


class Stack<T> {
    private T[] elements;

    public Stack() {
        elements = (T[]) new  Object[0];
    }

    public void push(T element){
        T[] temp = (T[]) new Object[elements.length+1];
        for (int i=0; i<elements.length; i++){
            temp[i] = elements[i];
        }
        temp[elements.length] = element;
        elements = temp;
    }

    public T peek() throws EmptyStackException {
        if (isEmpty())
            throw new EmptyStackException();
        return elements[elements.length-1];
    }

    public T pop() throws EmptyStackException {
        if (isEmpty())
            throw new EmptyStackException();
        T pop = elements[elements.length-1];
        T[] temp = (T[]) new Object[elements.length-1];
        for (int i=0; i<elements.length-1; i++){
            temp[i] = elements[i];
        }
        elements = temp;
        return pop;
    }

    public boolean isEmpty(){
        return elements.length == 0;
    }
}



public class StackTest {



    public static void main(String[] args) {
        Scanner jin = new Scanner(System.in);
        int k = jin.nextInt();
        System.out.println("Test#"+k);
        if ( k == 0 ) {
            System.out.println("testing: Stack::push(T) , Stack::pop():T , T is Integer");
            int n = jin.nextInt();
            Stack<Integer> stack = new Stack<Integer>();
            System.out.println("Pushing elements:");
            for ( int i = 1 ; i <= n ; ++i ) {
                if ( i > 1 ) System.out.print(" ");System.out.print(i);
                stack.push(i);
            }
            System.out.println();
            System.out.println("Poping elements:");
            for ( int i = n ; i >= 1 ; --i ) {
                if ( i < n ) System.out.print(" ");
                System.out.print(stack.pop());
            }
            System.out.println();
        }
        if ( k == 1 ) {
            System.out.println("testing: Stack::push(T) , Stack::pop():T , T is String");

            int n = jin.nextInt();
            Stack<String> stack = new Stack<String>();
            System.out.println("Pushing elements:");
            for ( int i = 0 ; i < n ; ++i ) {
                if ( i > 0 ) System.out.print(" ");
                String next = jin.next();System.out.print(next);
                stack.push(next);
            }
            System.out.println();
            System.out.println("Poping elements:");
            for ( int i = 0 ; i < n ; ++i ) {
                if ( i > 0 ) System.out.print(" ");
                System.out.print(stack.pop());
            }
        }
        if ( k == 2 ) {
            System.out.println("testing: Stack::push(T) , Stack::pop():T , Stack::isEmpty():boolean, T is Double");

            Stack<Double> stack = new Stack<Double>();
            System.out.println("Pushing elements:");
            boolean flag = false;
            while ( jin.hasNextDouble() ) {
                double d = jin.nextDouble();
                stack.push(d);
                if ( flag ) System.out.print(" ");
                System.out.printf("%.2f",d);
                flag = true;
            }
            int i = 0;
            System.out.println();
            System.out.println("Poping elements:");
            while ( ! stack.isEmpty() ) {
                if ( i > 0 ) System.out.print(" ");++i;
                System.out.printf("%.2f",stack.pop());
            }
        }
        if ( k == 3 ) {
            System.out.println("testing: Stack::push(T) , Stack::pop():T , Stack::isEmpty():boolean , Stack::peek():T , T is Long");

            int n = jin.nextInt();
            Stack<Long> stack = new Stack<Long>();
            LinkedList<Long> control_stack = new LinkedList<Long>();
            boolean exact = true;
            for ( int i = 0 ; exact&&i < n ; ++i ) {
                if ( Math.random() < 0.5 ) {//add
                    long to_add = (long)(Math.random()*456156168);
                    stack.push(to_add);control_stack.addFirst(to_add);
                }
                else {
                    exact &= control_stack.isEmpty()==stack.isEmpty();
                    if ( exact&&! stack.isEmpty() ) {
                        if ( Math.random() > 0.7 ) exact &= control_stack.removeFirst().equals(stack.pop());
                        else exact &= control_stack.peekFirst().equals(stack.peek());
                    }
                }
            }
            System.out.println("Your stack outputs compared to the built in java stack were the same? "+exact);
        }
        if ( k == 4 ) {
            System.out.println("testing: Stack::pop():T , Stack::isEmpty():boolean , Stack::peek():T , T is Long");

            Stack<Date> test_stack = new Stack<Date>();

            System.out.println("Stack empty? "+test_stack.isEmpty());
            try {
                test_stack.pop();
                System.out.println("NO exeption was thrown when trying to pop from an empty stack!");

            } catch(Exception e) {
                System.out.print("Exeption thrown when trying to pop from an empty stack ");
                System.out.println(e.getClass().getSimpleName());
            }
            try {
                test_stack.peek();
                System.out.println("NO exeption was thrown when trying to peek in an empty stack!");
            } catch(Exception e) {
                System.out.print("Exeption thrown when trying to peek in an empty stack ");
                System.out.println(e.getClass().getSimpleName());
            }
        }
    }

}