Resizing an array of objects - c++

Question

i'm trying to do a homework in c++ where I can't use STD container classes such as vector,map,etc. Suppose we have the following archive:
2
El juego de Ender-Orson Scott-Tor Books-980.275.246-1985-6000
890365.2
2
The following-Lily Tyler-Tor Books-980.275.246-1985-6000
890365.2
For explanation purposes lets assume the number 2 means that a book is from X category, in this case 2 means is a fiction book, the next line after 2 is just the basic book data (name,author,publishing house,isbn,year,price) and the next line after that is just something that we are going to call CCF that is just another code for these types of books from the fiction category.
I'm just stuck on the next following part, I do know how to create an array of objects without container classes, but I do not know how to resize this array, i've been hearing about realloc, but i don't know how to use it with object array types. Libro is the parent of Ficcion and i'm trying to store Ficcion types in a polymorphic array of Libro because later on I have to introduce more classes in the same array, but for learning purposes i'm trying to resize with just the ficcion class, that being said, I do know the next following code is wrong because i'm using malloc and allocating the child object with new and then reallocating, but as I said I don't really get how to do this at all cause if you see the code you can tell that a new child object is created every 3 times inFile has executed getline, if you think something's missing please let me know, but I think what i've exposed covers the main issues of this question. I'm just asking for some enlightment of information when you have to deal with these types of arrays and you need to resize them, and I also know this would be way more easier with the container class but I can't use it this time. Thanks in advance! have a great day/night!
void BookManager::dataLoading(char* fileName){
//Arbitrary size to be resized later on (this is the array declared as **libro in the .h file)
libros = (Libro**)malloc(1 * sizeof(Libro**));
//file-in variable
std::ifstream inFile(fileName);
char type[10];
//counter
int i = 0;
//First getline
while (inFile.getline(type,sizeof(inFile)) && i < 2){
//Book Info; Second Getline
char bookInfo[100];
inFile.getline(bookInfo, sizeof(inFile));
//Additional book information; Third getline
char additional[60];
inFile.getline(additional, sizeof(inFile));
//Child creation
if (type[0] == '2'){
this->separateData(bookInfo);
//Ficcion constructor creating an object to store in the libros polymorphic array
libros[i] = new Ficcion(this->bookData[0], this->bookData[1], this->bookData[2], atof(this->bookData[3]), atoi(this->bookData[4]), atoi(this->bookData[5]), atof(additional));
}
i++;
//Failed reallocating
libros = (Libro**)realloc(libros, i+1 * sizeof(Libro**));
}
// This one is just testing if the array worked but i get an unhandled exception when i=1;
for (int i = 0; i < 2; i++){
std::cout << libros[i]->getTitulo() << '\n';
}
inFile.close();
}
UPDATE solution:
Since this is an array of pointers, as suggested down below i created a function where it resizes it and deletes the old one, returning the new one with the old data and a free space to store. So far this is working, thanks a lot guys!
Libro** BookManager::resize(Libro** arr,int size){
Libro** resized = new Libro*[size];
for (int i = 0; i < size-1; i++){
resized[i] = arr[i];
}
delete[]arr;
return resized;
}

Answer 1

malloc, realloc, etc.. are C library functions. Your question carries the C++ tag, not C.
In C++, objects are allocated with new, and deallocated with delete. This includes arrays.
To resize an existing array, you use new to allocate a new array, with the new size, copy into it the elements in the existing array, then deallocate the old array with delete.
(This is not 100% technically true, but this is likely what you are expected to do as part of your assignment).