How do I insert char* to array of structures? - c

Question

the task is to dynamically allocate memory for the array of structures and then fill them from keyboard. I was able to dynamically allocate and fill amount of pages for each of the struct instance in array, but when I try to add char* to it by doing something like:
strcpy(myArray[i]->author, authorName);
But every time I get segmentation error, so what am I doing wrong?
Is it possible that problem is actually in memory allocation?
Here is the code
#include <stdlib.h>
#include <string.h>
struct Book {
char* author;
char* title;
int pages;
int pubYear;
int copies;
};
void allocList(struct Book **myArray, int booksAmount);
void fillKeyboard(struct Book **myArray, int booksAmount);
int main(void) {
struct Book *booksList = NULL;
int booksAmount = 3;
allocList(&booksList, booksAmount);
fillKeyboard(&booksList, booksAmount);
return 0;
}
void allocList(struct Book **myArray, int booksAmount) {
*myArray = (struct Book*) malloc(sizeof(struct Book) * 100);
printf("memory for %d books was allocated \n", booksAmount);
}
void fillKeyboard(struct Book **myArray, int booksAmount) {
int i = 0;
char* authorName = "author name";
while (booksAmount--) {
printf("book number %d \n", i + 1);
printf("enter amount of pages: ");
scanf("%d", &(*myArray)[i].pages);
printf("\nenter author: ");
strcpy(myArray[i]->author, authorName);
printf("%s is \n", authorName);
i++;
printf("\n");
}
}
Thank you.

Answer 1

myArray[i].author is a string.
so (in C) an array of char.
as an array you need to allocate it with a malloc
myArray[i].author=malloc(sizeof(char) * 100);
your while loop should look like this:
while (booksAmount--) {
myArray[i].author=malloc(sizeof(char) * 100);
printf("book number %d \n", i + 1);
printf("enter amount of pages: ");
scanf("%d", &(myArray)[i].pages);
printf("\nenter author: ");
strcpy(myArray[i].author, authorName);
printf("%s is \n", authorName);
i++;
printf("\n");
}
keep in mind that 100 is a "magic number" so if the author name is longer than 100 character it's not going to work
edit: same thing with the title, you need to allocate the needed memory in your array's element

Answer 2

If you care about memory, you should not create an array of 100 books. A good way to avoid such allocations is linked lists, so your program will always allocate just the needed memory. Your Book struct would look like this:
struct Book {
char* author;
char* title;
int pages;
int pubYear;
int copies;
struct Book *next;
};
The program will certainly be a bit more complex, but the result is a clean memory usage, and a truly dynamic program.