export class Stack<T> {
    private _store: T[];
    private top: number;

    constructor() {
        this.top = 0;
        this._store = [];
    }

    public clear(): void {
        this._store = [];
        this.top = 0;
    }

    public peek(): T {
        return this._store[this.top - 1];
    }

    public pop(): T {
        if (this.top > 0) {
            return this._store[--this.top];
        } else {
            throw new Error("Stack is empty");
        }
    }

    public push(el: T): void {
        this._store[this.top++] = el;
    }

    public isEmpty(): boolean {
        return this.top === 0;
    }
}