错误：在 C++ 中的 find 中，二进制表达式（'book' 和 'const int'）的操作数无效

Question

class book{
public:
   void setNameOfAuthor(string nameOfAuthor);
   string getNameOfAuthor();
   void setBookId(int bookid);
   int getBookId();
   bool operator==(const book& rhs)const;
   const int operator*()const;
private:
    string m_nameOfAuthor;
    int m_bookId;
};

class bms{
    private:
        vector<book> m_books;
    public:
        void addNewBook(book& booktoadd);
        void deleteBook();
        void displayBook();  
};

bool book::operator==(const book& rhs)const{
    return m_bookId == rhs.m_bookId;
}

const int book::operator*()const{
    return m_bookId;
}

void bms::deleteBook(){
    int booid;
    auto itr = find(m_books.begin(), m_books.end(), booid); ------>issue is here 
    if( itr != m_books.end()){
        m_books.erase(itr);
    }else{
        cout<<"book is not found!!"<<endl;
    }
}

im working on book management system project , trying to delete a book in find i get error as 
Library/Developer/CommandLineTools/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/algorithm:919:22: error: invalid operands to binary expression ('book' and 'const int')

 if (*__first == __value_) 

所以我尝试重载 == 运算符和 * 运算符，但无法解决我的问题，没有找到我做错的地方

在查找我是否调试时我认为问题是

find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
{
    for (; __first != __last; ++__first)
        if (*__first == __value_)-------------> issue seems to be hereis here 
            break;
    return __first;
}

因为我重载了 == 运算符，所以比较应该发生在 int 和 int 之间，我不明白为什么在 book 对象和 int 之间发生比较。请帮忙

Answer 1

如果您想通过 id 查找一本书，您可以使用

std::find_if

和 lambda 表达式

auto itr = find_if(
    m_books.begin(), 
    m_books.end(), 
    [=](const Book& b) { return b.getBookId() == booid; }
);