#include <iostream>
#include<cstring>
using namespace std;
class Book
{
private:
    int num;                           //该书的数量
    double price;                    //该书的价格
    char * bkname;                    //该书的名称，取值可能为“algorithm”“c++”等
    static double sum;                  //所有库存书的价格总和
    static int counter;              //书店库存书的总数
public:
    Book() :num(0), price(0){ strcpy(bkname, "no name"); }
    Book(int n, double p, char * b);                           //构造
    Book(Book & b);                          //复制构造
    ~Book();                           //析构函数                              
    void print() const;              //输出书的名称、单价和数量（已给出）
    void set(int, double);           //设置数量、价格(已给出)
    void set(char *);                //设置书的名称
    static double getAveragePrice(); //计算所有库存书的平均价格
    friend Book& compare(Book &, Book &);  //比较两类书
};//end of class
double Book::sum = 0;
int Book::counter = 0;
Book::Book(int n, double p, char *a){
    num = n;
    price = p;
    if (a)
    {
        bkname = new char[strlen(a) + 1];
        strcpy(bkname, a);
    }
    else {
        bkname = new char[8];
        strcpy(bkname, "no name");
    }
    sum += price;
    counter += num;
}
Book::Book(Book & b1)
{
    num = b1.num;
    price = b1.price;
    if (b1.bkname)
    {
        bkname = new char[strlen(b1.bkname) + 1];
        strcpy(bkname, b1.bkname);
    }
    else {
        bkname = new char[8];
        strcpy(bkname, "no name");
    }
    cout << bkname << "   copy  !!" << endl;

}
Book :: ~Book(){
    delete[] bkname;
}

//比较两类书b1和b2（compare(b1,b2)）,返回库存量大的书,用友元实现
Book & compare(Book & b1, Book & b2)
{
    if (b1.num >= b2.num)
        return b1;
    else
        return b2;
}
double Book::getAveragePrice(){
    double AveragePrice;
    AveragePrice = sum / counter;
    return AveragePrice;
}
void Book::print() const
{
    cout << "Book is :" << bkname << "/" << num << "/" << price << endl;
}

void Book::set(char * a)        //设置书的名称
{
    if (a)
    {
        bkname = new char[strlen(a) + 1];
        strcpy(bkname, a);
    }
    else {
        bkname = new char[8];
        strcpy(bkname, "no name");
    }

}
void Book::set(int n, double p)
{
    num = n; price = p;
}

void main()
{
    char nm[] = "c++";
    Book b[3] = { Book(60, 32.5, "English"), Book(20, 40.5, nm) };
    for (int i = 0; i<3; i++)
    {
        b[i].print();
    }
    cout << "average price = " << Book::getAveragePrice() << endl;//输出平均价格  

    cout << "**********************" << endl;
    b[1].set(20, 30.5);
    b[2].set(100, 35.5);
    b[1].set("Math");
    b[2].set("Java");

    for (int j = 0; j<3; j++)
    {
        b[j].print();
    }

    cout << "average price = " << Book::getAveragePrice() << endl;//输出平均价格  
    cout << "b[0] compare with b[2]，bigger one——";
    compare(b[0], b[2]).print();

}
用vc6.0编译时没有报错，但不能运行。
vs2013报错“ error C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.”不会改，，求指导。。

还是不行呀，好像是默认构造函数有问题，而且那个对象数组的初始化也有问题。。麻烦你再看看。。

如果用vc的话就不会有着个警告。。好像是默认构造和对象数组初始化有问题。。