Error in stack code

[CodeX Pro]

Problem solved so I have removed the codes

[kjkrum]

"during the execution it shows some logical error" - post it.

BTW, if this isn't homework... just use a Deque (Java Platform SE 6).

[CodeX Pro]

"during the execution it shows some logical error" - post it.

BTW, if this isn't homework... just use a Deque (Java Platform SE 6).

No its not home work and I have figured out the error and have solved it

[DarrylBurke]

Problem solved so I have removed the codes

This is a forum, where we share problems and their possible solutions.

For the record, this is the original post:

hello all,

I want to implement stack data structure using interfaces and in such a way that it works for all kinds of data types. Which we will specify by JStack<Integer> or JStack<String> etc.

I have done the following but during the execution it shows some logical error in JStack class please help me out.

StackInterface.java

 package DataStructures;

 /**
 *
 * @author CodeX Pro
 */
 public interface StackInterface<ObjectDataType> {

 /**
 *
 * @param item This method push the item passed into the stack
 */
 public abstract void push(ObjectDataType item);

 /**
 *
 * @return This method removes the top element from the stack
 */
 public abstract ObjectDataType pop();

 /**
 *
 * @return This method returns whether the stack is empty or not
 */
 public abstract boolean isEmpty();

 /**
 *
 * @return This Methods returns the top element of the stack
 */
 public abstract ObjectDataType peek();

 /**
 *
 * @return This method returns the size of the stack
 */
 public abstract int size();

 }

JStack.java (This contains the implementations of the methods)

 package DataStructures;

 import java.util.LinkedList;

 /**
 *
 * @author Codex Pro
 */
 public class JStack<E> implements StackInterface<E>{

 private LinkedList<E> list = new LinkedList<>();

 public JStack(){
 list=null; 
 }

 @Override
 public void push(E item) {
 list.addFirst(item);
 }

 @Override
 public E pop() {
 return list.removeFirst();
 }

 @Override
 public boolean isEmpty() {
 return list.isEmpty();
 }

 @Override
 public E peek() {
 return list.getFirst();
 }

 @Override
 public int size() {
 return list.size();
 }

 }

StackDriver.java : This is a test class for checking the working of the JStack

 package DataStructures;

 import java.util.Scanner;

 /**
 *
 * @author CodeX Pro
 */
 public class StackDriver {

 private JStack<Integer> stack;

 public StackDriver() {
 this.stack = new JStack<>();
 }

 public static void main(String[] args) {
 StackDriver obj = new StackDriver();
 int item, choice;
 boolean proceed = true;
 Scanner sc = new Scanner(System.in);
 while (proceed) {
 System.out.println("Menu\n");
 System.out.println("1. Push");
 System.out.println("2. Pop");
 System.out.println("3. Peek");
 System.out.println("4. Size");
 System.out.println("\nEnter your choice :-");
 choice = sc.nextInt();
 switch (choice) {

 case 1:
 System.out.println("Enter an item to be entered into the stack :");
 item = sc.nextInt();
 obj.stack.push(item);
 System.out.println("Element " + item + " pushed into stack");
 break;

 case 2:
 if (!obj.stack.isEmpty()) {
 item = obj.stack.pop();
 System.out.println("Element " + item + " poped from stack");
 } else {
 System.out.println("Stack Underflow. No items found in stack");
 }
 break;

 case 3:
 if (!obj.stack.isEmpty()) {
 item = obj.stack.peek();
 System.out.println("Top Element in the stack is " + item);
 } else {
 System.out.println("Stack Underflow. No items found in stack");
 }
 break;

 case 4:item=obj.stack.size();
 System.out.println("Size of Stack is :- "+item);
 break;

 default:
 System.out.println("Wrong Choice!");
 }
 System.out.println("\nDo you want to continue[true/false] :-");
 proceed = sc.nextBoolean();
 }
 }
 }

db

THREAD CLOSED