程序代码：

#include <iostream>
#include <cstring>
using namespace std;

class Books
{
    private:
        float Price;
        string Author;
    public:
        Books(float price, string author);
        void ShowInfo();
        Books& operator =(const Books &bookname);
};

Books& Books::operator = (const Books &bookname)
{
    if (&bookname == this)
        return *this;
    else
    {
        Books temp(bookname.Price, bookname.Author);
        return temp;
    }
}

Books::Books(float price, string author)
{
    Price = price;
    Author = author;
}

void Books::ShowInfo()
{
    cout << "Book Price" << '\t' << Price << endl;
    cout << "Book Author" << '\t' << Author << endl;
}

int main()
{
    Books APEU(67, "Bob");
    APEU.ShowInfo();
    return 0;
}

程序代码：

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

class Books
{
    private:
        float Price;
        string Author;
    public:
        Books(float price, string author);
        void ShowInfo();
        Books operator =(const Books &bookname);
};

Books Books::operator = (const Books &bookname)
{
    if (&bookname == this)
        return *this;
    else
        return Books(bookname.Price, bookname.Author); //这里
}

Books::Books(float price, string author)
{
    Price = price;
    Author = author;
}

void Books::ShowInfo()
{
    cout << "Book Price" << '\t' << Price << endl;
    cout << "Book Author" << '\t' << Author << endl;
}

int main()
{
    Books APEU(67, "Bob");
    APEU.ShowInfo();
    return 0;
}