fix: remove duplicate method definitions in main()

Author: gowtham1412-p

src/main/java/com/thealgorithms/datastructures/stacks/StackUsingLinkedList.java

@@ -199,135 +199,6 @@ public static void main(String[] args) {
             System.out.println("Caught exception: " + e.getMessage());
         }
 
-        /**
-         * Checks if this stack is empty.
-         * Time Complexity: O(1)
-         *
-         * @return {@code true} if this stack contains no elements, {@code false} otherwise
-         */
-        public boolean isEmpty() {
-            return top == null;
-        }
-
-        /**
-         * Returns the number of elements in this stack.
-         * Time Complexity: O(1)
-         *
-         * @return the number of elements in this stack
-         */
-        public int size() {
-            return size;
-        }
-
-        /**
-         * Removes all elements from this stack.
-         * Time Complexity: O(1)
-         */
-        public void clear() {
-            top = null;
-            size = 0;
-        }
-
-        /**
-         * Returns a string representation of this stack.
-         * The string representation consists of a list of the stack's elements
-         * from top to bottom, enclosed in square brackets ("[]").
-         *
-         * @return a string representation of this stack
-         */
-        @Override
-        public String toString() {
-            if (isEmpty()) {
-                return "[]";
-            }
-
-            StringBuilder sb = new StringBuilder("[");
-            Node<T> current = top;
-            while (current != null) {
-                sb.append(current.data);
-                if (current.next != null) {
-                    sb.append(", ");
-                }
-                current = current.next;
-            }
-            sb.append("]");
-            return sb.toString();
-        }
-
-        /**
-         * Demonstration of the StackUsingLinkedList implementation.
-         *
-         * @param args command line arguments (not used)
-         */
-        public static void main(String[] args) {
-            // Example 1: Stack of Integers
-            System.out.println("=== Integer Stack Demo ===");
-            StackUsingLinkedList<Integer> intStack = new StackUsingLinkedList<>();
-
-            // Push elements
-            intStack.push(10);
-            intStack.push(20);
-            intStack.push(30);
-            intStack.push(40);
-            System.out.println("Stack after pushing 10, 20, 30, 40: " + intStack);
-            System.out.println("Size: " + intStack.size());
-
-            // Peek
-            System.out.println("Top element (peek): " + intStack.peek());
-
-            // Pop elements
-            System.out.println("Popped: " + intStack.pop());
-            System.out.println("Popped: " + intStack.pop());
-            System.out.println("Stack after popping twice: " + intStack);
-            System.out.println("Size: " + intStack.size());
-
-            // Check if empty
-            System.out.println("Is stack empty? " + intStack.isEmpty());
-
-            // Pop remaining elements
-            intStack.pop();
-            intStack.pop();
-            System.out.println("Is stack empty after popping all? " + intStack.isEmpty());
-
-            // Example 2: Stack of Strings
-            System.out.println("\n=== String Stack Demo ===");
-            StackUsingLinkedList<String> stringStack = new StackUsingLinkedList<>();
-
-            stringStack.push("Hello");
-            stringStack.push("World");
-            stringStack.push("Java");
-            System.out.println("Stack: " + stringStack);
-            System.out.println("Top: " + stringStack.peek());
-            System.out.println("Popped: " + stringStack.pop());
-            System.out.println("Stack after pop: " + stringStack);
-
-            // Example 3: Exception handling
-            System.out.println("\n=== Exception Handling Demo ===");
-            StackUsingLinkedList<Integer> emptyStack = new StackUsingLinkedList<>();
-            try {
-                emptyStack.pop();
-            } catch (IllegalStateException e) {
-                System.out.println("Caught exception: " + e.getMessage());
-            }
-
-            try {
-                emptyStack.peek();
-            } catch (IllegalStateException e) {
-                System.out.println("Caught exception: " + e.getMessage());
-            }
-
-            // Example 4: Clear operation
-            System.out.println("\n=== Clear Operation Demo ===");
-            StackUsingLinkedList<Integer> stack = new StackUsingLinkedList<>();
-            stack.push(1);
-            stack.push(2);
-            stack.push(3);
-            System.out.println("Stack before clear: " + stack);
-            stack.clear();
-            System.out.println("Stack after clear: " + stack);
-            System.out.println("Is empty? " + stack.isEmpty());
-        }
-
         // Example 4: Clear operation
         System.out.println("\n=== Clear Operation Demo ===");
         StackUsingLinkedList<Integer> stack = new StackUsingLinkedList<>();