int array inside a struct inside a struct

Question

I am trying to achieve this... A single container which holds an array of structs and inside each of these structs are a single int array which represents an integer like so... 12,345 would be inside an int array[5]={1,2,3,4,5}

What is a way that this could be implemented. My main problem with this implementation is I get lost with all the pointers pointing everywhere and I start having garbage data all over and segfaults all over. Oh yeah by the way everything is dynamic. Well almost everything i guess if you have a struct Container which has a struct inside of that if the container is malloc'd then the struct inside of it is automatically malloc'd also so my guess would be

Container->struct.array

not sure????

Answer 1

you need to write malloc and free function of your struct and contianer yourself and call them everytime when you need a contianer or release its space, for example:

struct outside{
    struct inside *in;
};


struct inside{
    int *array;
};

struct outside *malloc_outside(size_t n) {
    int i;
    struct outside *o;
    o = (struct outside *)malloc(n*sizeof(struct outside));
    for(i=0;i<n;i++) {
        o->in = malloc(sizeof(struct inside));
        o->in->array = NULL;
    }
    return o;
}


void free_outside(struct outside *out) {
    free(out->in->array);
    free(out->in);
    free(out);
    return;
}

and malloc() array's space as how many you need after your malloc_outside()

it's easier to do in C++ by the constructor and destructor .

Answer 2

I am not sure i've completely understood, but have a look at the following code:

struct MyStruct {
    int *array;
};
struct Container {
    struct MyStruct *array;
};

And the allocation part would be like:

struct Container c;
c.array = malloc(sizeof(struct MyStruct) * NUM_STRUCTS);

for (i = 0; i < NUM_STRUCTS; ++i) {
    c.array[i].array = malloc(get_num_of_digits(12.345) * sizeof(int));    
}

I haven't tested this code, but should do the job :P. Good luck.

Answer 3

struct that contains an array of structs that contain a array of integers. no pointers, as u asked

#define SIZE (8)

typedef struct {
    struct data {
        int idata[SIZE];
    };
    struct data arr[SIZE];
}record;

//or
struct data {
    int idata[SIZE];
};

typedef struct data arr[SIZE];