c++ - 构造函数问题

Question

我必须实现一个类来表示图书馆的书籍。对于每本书，我必须指定:标题、作者、ISBN 代码、出版年份和价格。然后我需要创建一个包含图书馆中所有书籍的数组。这是我处理过的代码，这是错误:

error C2512: 'Book' : no appropriate default constructor available

我做错了什么？

    Book.h
      #ifndef BOOK_H
      #define BOOK_H

#include<string>

using namespace std;

class Book
{
private:
    string title;
    string author;
    string code; 
    string edit;
    int year;
    double price;
public:
    Book();
    Book(string t, string a, string c, string e, int y, double p)
    {
        title=t;
        author=a;
        code=c;
        edit=e;
        year=y;
        price=p;
    }
    string GetTitle() const { return title;}
    string GetAuthor() const { return author;}
    string GetCode() const {return code;}
    string GetEdit() const {return code;}
    int GetYear() const {return year;}
    double GetPrice() const {return price;}
};
#endif




Library.h
 #ifndef LIBRARY_H
 #define LIBRARY_H
 #include"Book.h"
 #include<iostream>

 class Library
 {
  private:
    Book books[50];
    int index;
   public:
    Library()
    {
        index=0;
    }
    void Add(Book book)
    {
        books[index]=book;
        index++;
    }
    void PrintAll()
    {
        for (int i = 0; i < index; i++)
        {
            Book book=books[i];
            cout<<book.GetTitle()<<":"
    <<book.GetAuthor()<<":"<<book.GetYear()<<endl;
        }
    }
  };
  #endif

   main.cpp


     #include"Library.h"
int main()
{
    Library library;
    Book b1("title1","author1","code1","edit1",1900,34.5);
    library.Add(b1);
    Book b2("title2","author2","code2","edit2",1990,12);
    library.Add(b2);
    library.PrintAll();
}

Answer 1

现在，由于您已经定义了一个带有 6 个参数的构造函数，因此编译器不会为您生成默认构造函数。因此，您还需要定义一个默认构造函数来支持诸如 void Add(Book book) {} 之类的代码行。可能如下所示:

Book() : title(""), author(""), code(""), edit(""), year(1900), price(0.0) 
{}