class Node{
private String value;
private Node next;
public Node(String value){
this.value= value;
}
public void setNext(Node next){
this.next= next;
}
public Node getNext(){
return this.next;
}
public void setValue(String value){
this.value= value;
}
public String getValue(){
return this.value;
}
}
class MyStack{
private Node bottom;
private Node top;
private int length;
public MyStack(String value){
top = new Node(value);
bottom= top;
this.length++;
}
public String peek(){
if (this.length ==0){
System.out.println("The stack is empty, cannot pop");
return;
}
return this.top.getValue();
}
public String pop(){
if (this.length ==0){
System.out.println("The stack is empty, cannot pop");
return;
}
Node removedTop =top;
top= removedTop.getNext();
this.length--;
if (removedTop == bottom){
bottom=null;
}
return removedTop.getValue();
}
public void push(String value){
Node newTop = new Node(value);
newTop.setNext(top);
top=newTop;
this.length++;
}
public boolean isEmpty(){
return this.length==0;
}
/*public static void main(String args[]){
MyStack stack = new MyStack("uno");
stack.push("dos");
stack.push("tres");
stack.push("cuatro");
stack.push("cinco");
System.out.println(stack.peek());
System.out.println(stack.pop());
System.out.println(stack.pop());
while(!stack.isEmpty()){
System.out.println(stack.pop());
}
}*/
}
class Main {
private Node head;
private Node tail;
private int length=0;
public Main(String value){
this.head = new Node(value);
this.tail = head;
length++;
}
public void prepend(String value){
Node newHead = new Node(value);
newHead.setNext(head);
head= newHead;
length++;
}
public void append(String value){
Node newTail= new Node(value);
tail.setNext(newTail);
tail=newTail;
length++;
}
public void insert(int index, String value){
Node currentNode = head;
Node previousNode=head;
int currentIndex=0;
if (index ==0){
prepend(value);
return;
}
while (currentIndex < index && currentNode != null){
previousNode = currentNode;
currentNode = currentNode.getNext();
currentIndex++;
}
Node newNode = new Node(value);
previousNode.setNext(newNode);
newNode.setNext(currentNode);
}
public void delete(int index){
Node currentNode = head;
Node previousNode=head;
int currentIndex=0;
while (currentIndex < index && currentNode != null){
previousNode = currentNode;
currentNode = currentNode.getNext();
currentIndex++;
}
if (index ==0){
head= head.getNext();
} else {
previousNode.setNext(currentNode.getNext());
}
}
public void printAll(){
Node node = head;
while (node != null){
System.out.println(""+node.getValue());
node = node.getNext();
}
}
public static void main(String[] args) {
/*Main linkedList = new Main("1");
linkedList.append("2");
linkedList.append("3");
linkedList.append("4");
linkedList.prepend("0");
linkedList.prepend("-1");
linkedList.insert(1, "-0.5");
linkedList.insert(3, "0.5");
linkedList.insert(7, "3.5");
linkedList.insert(0, "-2");
linkedList.printAll();
linkedList.delete(9);
linkedList.printAll();*/
MyStack stack = new MyStack("uno");
//System.out.println(stack.peek());
stack.push("dos");
//System.out.println(stack.peek());
stack.push("tres");
//System.out.println(stack.peek());
stack.push("cuatro");
//System.out.println(stack.peek());
stack.push("cinco");
//System.out.println(stack.peek());
//System.out.println(stack.pop());
//System.out.println(stack.pop());
while(!stack.isEmpty()){
System.out.println(stack.pop());
}
// System.out.println(stack.pop());
}
}
/*class Node{
private String value;
private String next;
public Node(String value){
this.value = value;
}
public void setNext(String next){
this.next = next;
}
public String getNext(String next){
return this.next;
}
public String getValue(String value){
return this.value;
}
}*/
class Stack{
private Node bottom;
private Node top;
private int length;
public Stack(String value){
top = new Node(value);
bottom= top;
}
public String peek(){
return this.top.getValue();
}
public String pop(){
Node removedTop =top.getNext();
top= removedTop.getNext();
this.length--;
if (removedTop == bottom){
bottom=null;
}
return removedTop.getValue();
}
public void push(String value){
Node newTop = new Node(value);
newTop.setNext(top);
top=newTop;
this.length++;
}
public void isEmpty(){
return this.length==0;
}
public static void main(String args[]){
MyStack stack = new MyStack("uno");
stack.push("dos");
stack.push("tres");
stack.push("cuatro");
stack.push("cinco");
System.out.println(stack.peek());
System.out.println(stack.pop());
System.out.println(stack.pop());
while(!stack.isEmpty()){
System.out.println(stack.pop());
}
}
}
