implement.ts

export class Numbers {
	#data: number[];
	#max = 0;

	addNumber(num: number) {
		this.#max = Math.max(num, this.#max);
		this.#data.push(num);
	}

	getAll(): number[] {
		return this.#data;
	}

	deleteLast() {
		this.#data = this.#data.slice(0, this.#data.length - 2);
	}

	getMax(): number {
		return this.#max;
	}
}

interface.ts

interface Numbers {
	addNumber(num: number): void;
	getAll(): number[];
	deleteLast(): void;
}