1/*
2 * Copyright (c) 2023 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15declare class Stack<T> {
16    constructor();
17    push(element: T): void;
18    pop(): T;
19    size(): number;
20}
21declare interface GeometricShape {
22    /**
23     * Calculates the area of the shape.
24     * @returns {number} The area of the shape.
25     */
26    calculateArea(): number;
27}
28/**
29 * A function to capitalize the first letter of a string.
30 * @param {string} str - The input string.
31 * @returns {string} The capitalized string.
32 */
33declare function capitalizeFirstLetter(str: string): string;
34