#include "pch.h"

#include<iostream>

using namespace std;

const float PI = 3.1415926;

int    main() {

    int iType;

    float readius, a, b;

    while (true){

        cout << "图形的类型为？(1-圆形 2-长方形 3-正方形)";

        cin >> iType;

        switch (iType) {

        case :

            cout << "请输入圆形的直径";

            cin >> readius;

            cout << "圆的面积为" << readius * PI << "平方厘米" << endl;

            break;

        case :

            cout << "矩形的长为:";

            cin >>a;

            cout << "矩形的宽位";

            cin >> b;

            cout << "矩形的面积为:" << a * b << "平方厘米" << endl;

            break;

        case :

            cout << "请输入正方形的边长";

            cin >> a;

            cout << "正方形面积为" << a * a << "平方厘米" << endl;

        }

    }

}