声明类Shape以及它的3个派生类：Circle、Square、Rectangle， 用虚函数分别计算几种图形的面积、周长，编写程序，建立基 类指针数组，每个指针均指向一个派生类对象，利用基类指针 遍历元素对象，求取所有图形面积之和。请绘制UML类图

好的，我理解了你的问题。以下是UML类图和相应的C++代码实现。

UML类图：

+--------------+
|     Shape    |
+--------------+
| -name: string|
+--------------+
|+calcArea():  | 
|+calcPeri():  | 
+--------------+
       /_\
        |
        |
+--------------+
|    Circle    |
+--------------+
| -radius: double|
+--------------+
|+calcArea():  | 
|+calcPeri():  | 
+--------------+
       /_\
        |
        |
+--------------+
|    Square    |
+--------------+
| -side: double|
+--------------+
|+calcArea():  | 
|+calcPeri():  | 
+--------------+
       /_\
        |
        |
+--------------+
|   Rectangle  |
+--------------+
| -length: double|
| -width: double|
+--------------+
|+calcArea():  | 
|+calcPeri():  | 
+--------------+

C++代码实现：

#include<iostream>
#include<string>

using namespace std;

class Shape {
protected:
    string name;
public:
    Shape(string n) : name(n) {}
    virtual double calcArea() = 0;
    virtual double calcPeri() = 0;
};

class Circle : public Shape {
private:
    double radius;
public:
    Circle(string n, double r) : Shape(n), radius(r) {}
    double calcArea() { return 3.14 * radius * radius; }
    double calcPeri() { return 2 * 3.14 * radius; }
};

class Square : public Shape {
private:
    double side;
public:
    Square(string n, double s) : Shape(n), side(s) {}
    double calcArea() { return side * side; }
    double calcPeri() { return 4 * side; }
};

class Rectangle : public Shape {
private:
    double length, width;
public:
    Rectangle(string n, double l, double w) : Shape(n), length(l), width(w) {}
    double calcArea() { return length * width; }
    double calcPeri() { return 2 * (length + width); }
};

int main() {
    Shape *arr[] = { new Circle("Circle", 5), new Square("Square", 6), new Rectangle("Rectangle", 3, 4) };
    double totalArea = 0;
    for (int i = 0; i < 3; i++) {
        totalArea += arr[i]->calcArea();
    }
    cout << "Total Area: " << totalArea << endl;
    return 0;
}

这个程序使用了基类指针数组来指向不同的派生类对象，并使用`calcArea()`函数计算每个图形的面积，最后求取所有图形面积之和。注意：这个程序只是一个示例，实际中可能需要更多的错误检查和数据输入。