如何在 C 中使用动态数组向结构中添加数据？

Question

this is my first post on Stack-overflow, I hope I'm not posting a duplicate question but a I couldn't find any reference on this matter. I have a "library management system" project in C, where I have to add books to the "library" by using an array of pointers pointing to the structures (books). the problem is I tried a lot of things and nothing worked so far and last thing I tried gave me a lot of errors.

So basically I have this system in which there is a main menu, the user chooses an input to: a. Add/return book b. Take a book c. Print books by times borrowed from the library d. Quit

the rest of the options are easy to deal with if I understand how to add data into a structure. my code so far looks like this:

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

#define BOOK_NUM 4
#define NAME_LENGTH 200
#define AVAILABLE 10
#define NOT_AVAILABLE 20

int menu_on=1;

//~~~~~~~~~~~~~~~~~~~~~~

typedef struct book {
    char name[NAME_LENGTH];
    char author[NAME_LENGTH];
    int available;
    int times_borrowed;
} book;

book* Books[BOOK_NUM];

void AddBook()
{
    char name[NAME_LENGTH];
    printf("Please enter book name:");
    scanf("%s", name);
    for (int i=0;i<BOOK_NUM;i++)
    {
        if(name!=Books[i]->name)
        {
            Books[i]= malloc(sizeof(book));
            if((Books[i]=NULL))
            {
                free(Books);
                free(Books[i]);
                exit(1);
            }
            strcpy(Books[i]->name, name); // here is the problem**
            printf("Please enter author name:");
            scanf("%s", Books[i]->author);
            Books[i]->available=AVAILABLE;
            Books[i]->times_borrowed=0;
            printf("The book %s was successfully added!\n", name);
            break;
        }
        else if ((name == Books[i]->name) && (Books[i]->available==AVAILABLE))
        {
            printf("This book is already in the library :)");
        }
        else if ((name == Books[i]->name) && (Books[i]->available==NOT_AVAILABLE))
        {
            ReturnBook(name); //this function is for later.
        }
    }
 
}

what I'm trying to do is just add one book at a time, allocate memory for it, and then the rest of the details. at most the "library" includes 4 books.

• available - if the book is borrowed or not (AVAILABLE/NOT-AVAILABLE)
• times_borrowed should be initialised when adding a new book since the new book is "never borrowed before"

The rest of the stuff can be done easily if I just know how to add these books and use the dynamic array with its content.

The error I receive is: EXC_BAD_ACCESS (code=1, address=0x0)

Answer 1

if((Books[i]==NULL))
 {
    free(Books);
    free(Books[i]);
    exit(1);
 }

Here, you should use == not = . Using = will make Books[i] = NULL .

And use strcmp for string comparison.