Since by now you know Stack can be implemented in various ways -
Linked List implementation or Array implementation...
Its all about achieving Stack behavior and your constraint adjustment as per your needs, you can go either way (use Arrays or Linked List)- here is one linked list implementation (Remember- you need to create your own linked list and do not use Java utility classes for such implementation), here is the code to help you understand:
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package Stack;
import java.util.Scanner;
// Stack Class
public class LinkedListImplementation {
public int size;
private Node node = null ;
LinkedListImplementation(){
new Node() ;
}
public boolean isEmpty() {
return node==null;
}
public int size() {
int size = 0;
Node temp = node;
while(temp !=null) {
temp = temp.next ;
size++;
}
return size;
}
public void push(String item) {
Node head = node;
node = new Node() ;
node.item = item;
node.next = head ;
}
public String pop() {
String item = node.getItem() ;
node = node.getNext() ;
return item;
}
public static void main(String args[]) {
Scanner sc = new Scanner(System.in) ;
LinkedListImplementation lstack = new LinkedListImplementation() ;
lstack.push("A");
lstack.push("B");
lstack.push("C");
lstack.push("D");
lstack.display();
System.out.println("");
System.out.println(lstack.size()) ;
lstack.pop();
lstack.display();
}
public void display() {
if(node == null)
return;
else {
Node temp = node;
while(temp!=null) {
System.out.print(temp.item+" -> ");
temp= temp.next;
}
}
}
}
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/* Node Class */
package Stack;
public class Node {
String item;
Node next ;
public Node(){
this.next = null;
this.item = null;
}
public String getItem() {
return item;
}
public void setItem(String item) {
this.item = item;
}
public Node getNext() {
return next;
}
public void setNext(Node next) {
this.next = next;
}
}
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This is very simple and easy implementation of Stack which provides all basic push, pop features..more features can be added as per needs.
