/**
 * A generic Stack implementation with Last-In-First-Out (LIFO) behavior.
 * @template T The type of elements stored in the stack.
 */
export declare class Stack<T> {
    private items;
    /**
     * Adds an item to the top of the stack.
     * @param item The item to push onto the stack.
     * @returns The new length of the stack.
     */
    push(item: T): number;
    /**
     * Removes and returns the item at the top of the stack.
     * @returns The removed item, or undefined if the stack is empty.
     */
    pop(): T | undefined;
    /**
     * Returns the item at the top of the stack without removing it.
     * @returns The top item, or undefined if the stack is empty.
     */
    peek(): T | undefined;
    /**
     * Checks if the stack is empty.
     * @returns True if the stack has no items, false otherwise.
     */
    isEmpty(): boolean;
    /**
     * Gets the number of items in the stack.
     * @returns The stack size.
     */
    size(): number;
    /**
     * Removes all items from the stack.
     */
    clear(): void;
    /**
     * Returns all items in the stack as an array (without modifying the stack).
     * The first element in the array is the bottom of the stack, the last is the top.
     * @returns An array containing all stack items.
     */
    toArray(): T[];
}