程序代码：

#include <iostream>
#include <string.h>
using namespace std;

class books
{
    private:
        char author[10];
        float price;
    public:
        books(char *au, float pri)
        {
            strcpy(author, au);
            price = pri;
        }
        void showprice()
        {
            cout << price <<endl;
        }
};

class m:private books
{
    private:
        int id;
    public:
        m(char *au, float pri)
        {
            books(char *au, float pri);
        }
        void setid(int x)
        {
            id = x;
        }
        void showid()
        {
            cout << id << endl;
        }
};

int main()
{
    m abc("Yes", 2.5);
    abc.setid(10);
//    abc.showprice();
    abc.showid();
    return 0;
}