Creating an always evolving **number** of structs[x] using x

Question

I don't know how to phrase the title better but I want to parse a file and depending on the number of x's returned, create x amount of similar structs that I will later fill individually with different values!

So if nb_structs is the number of structs I need to create, how would I create them?

This is the struct that has to be duplicated:

typedef struct graph {
    int id;
    int ant;
    int box;
    int *rooms;
}graph_t;

It won't let me just put

typedef struct graph[nb_structs]

and I don't know how to put it in a header file since nb_structs is determined in a function in my program!

(Also, my school won't let me use any other variables aside malloc, free, read and write for this project)

Answer 1

It's usually done like this:

int nb_structs=2;
graph_t* graphs = malloc(nb_structs * sizeof *graphs);
for (x = 0; x < nb_structs; x++)
{
   graphs[x].id = 123;
   ...
}