Question

我尝试在不同的结构中malloc一个结构数组。这甚至可能吗？我搜索了几个小时，我找不到任何关于如何正确做到的好解释。我想在“图书馆”中有一系列“书”。我需要malloc，所有东西都放在堆上而不是堆栈上。

struct book
{
        page *read_page;             //page is also a struct
        unsigned int id;
};

struct library
{
        book *any_book = static_cast<book*> (malloc (NBR_OF_BOOKS * sizeof(book)));

        for ( int book_counter = 0; book_counter < NBR_OF_BOOKS; book_counter++)
        {
            book[book_counter] = static_cast<book*> (malloc(sizeof(book)));
        }
        void* v = malloc(sizeof(book));
        any_book = static_cast<book*>(v);
};

我收到以下错误消息（第13行）：no match for 'operator=' (operand types are 'book' and 'book*')

Answer 1

因为这标记为c ++：

const int NBR_OF_PAGES=50;
const int NBR_OF_BOOKS=20;
struct book
{
    page *read_page;             //page is also a struct
    unsigned int id;
    book(){read_page = new page[NBR_OF_PAGES];}
    ~book(){delete[] read_page;}
};

struct library 
{
    book *any_book;
    library(){any_book = new book[NBR_OF_BOOKS];}
    ~library(){delete[] any_book;}
};

编辑::

可能的计划：

const int NBR_OF_PAGES=50;
const int NBR_OF_BOOKS=20;
struct page{
    unsigned int id;
    unsigned int getID(){return id;}
};
struct book
{
    page *read_page;             //page is also a struct
    unsigned int id;
    book(){read_page = new page[NBR_OF_PAGES];}
    ~book(){delete[] read_page;}

};

struct library  
{
    book *any_book;
    library(){any_book = new book[NBR_OF_BOOKS];}
    ~library(){delete[] any_book;}
};
#include <iostream>
int main(){
    library lib;
    lib.any_book[3].read_page[4].id=2;
    std::cout<<lib.any_book[3].read_page[4].getID()<<std::endl;
}

输出：2

malloc stuct中的一系列stuct

1 个答案:

可能的计划：