Java/DataStructures/Stacks/StackOfLinkedList.java at master · SetGeek/Java · GitHub

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/**
 *
 * @author Varun Upadhyay (https://github.com/varunu28)
 *
 */

// An implementation of a Stack using a Linked List

classStackOfLinkedList {

publicstaticvoidmain(String[] args) {

LinkedListStackstack = newLinkedListStack();
stack.push(1);
stack.push(2);
stack.push(3);
stack.push(4);
stack.push(5);

stack.printStack();

System.out.println("Size of stack currently is: " + stack.getSize());

stack.pop();
stack.pop();

System.out.println("Top element of stack currently is: " + stack.peek());

 }

}

// A node class

classNode {
publicintdata;
publicNodenext;

publicNode(intdata) {
this.data = data;
this.next = null;
 }
}

/**
 * A class which implements a stack using a linked list
 *
 * Contains all the stack methods : push, pop, printStack, isEmpty
 **/

classLinkedListStack {

Nodehead = null;
intsize = 0;

publicvoidpush(intx) {
Noden = newNode(x);
if (getSize() == 0) {
head = n;
 }
else {
Nodetemp = head;
n.next = temp;
head = n;
 }
size++;
 }

publicvoidpop() {
if (getSize() == 0) {
System.out.println("Empty stack. Nothing to pop");
 }

Nodetemp = head;
head = head.next;
size--;

System.out.println("Popped element is: " + temp.data);
 }

publicintpeek() {
if (getSize() == 0) {
return -1;
 }

returnhead.data;
 }

publicvoidprintStack() {

Nodetemp = head;
System.out.println("Stack is printed as below: ");
while (temp != null) {
System.out.println(temp.data + " ");
temp = temp.next;
 }
System.out.println();

 }

publicbooleanisEmpty() {
returngetSize() == 0;
 }

publicintgetSize() {
returnsize;
 }

}