How do i assign pointer value inside array of pointers

Question

i have this error:

ID3.c:71:53: error: incompatible types when assigning to type ‘t_object’ {aka ‘struct object’} from type ‘t_object *’ {aka ‘struct object *’} 71 | (objects->v[sizeof(void *) * i]) = t_object_ctor(); | ^~~~~~~~~~~~~

i tried this:

&(objects->v[sizeof(void *) * i]) = t_object_ctor();

and tried this

*(objects->v[sizeof(void *) * i]) = t_object_ctor();

and this gives the same error

*((objects->v)+[sizeof(void *) * i]) = t_object_ctor();

this is the funcion the error is in: t_objects *t_objects_ctor(){ t_objects *objects =malloc(sizeof(t_objects));

    objects->size = 0;
    objects->y = 0;
    objects->x = 0;
    objects->x_size= malloc(sizeof(size_t) * RESONABLENUMBER);
    objects->v= malloc(sizeof(void *) * RESONABLENUMBER);
    for (int i = 0; i < RESONABLENUMBER; ++i) {
        *((objects->v) + sizeof(void *) * i) = t_object_ctor();
    }
    objects->b_size = 0;
    objects->b = NULL;
    
    return objects;
}

this is the function im assigning pointers from:

t_object *t_object_ctor(){
    t_object *object =malloc(sizeof(t_object));
    
    object->s = 0;
    object->x = NULL;
    object->y = 0;
    
    return object;
    
}

if objects is t_object * objects[] then it should just be objects[i] = t_object_ctor(); — cediwelli
– cediwelli, Commented Apr 3, 2022 at 8:19
objects is a pointer on struct that is named t_objects with 'v' that is a pointer to t_object (which i want to use as a array) — Bitter
– Bitter, Commented Apr 3, 2022 at 8:27

dulngix · Accepted Answer · 2022-04-03 08:33:44Z

1

Try this:

((t_object **)objects->v)[i] = t_object_ctor();

Full code like this:

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

#define RESONABLENUMBER 16
typedef struct t_objects {
    int size;
    int x, y;
    void *x_size;
    void *v;
    int b_size;
    char *b;
} t_objects;

typedef struct t_object {
    int s;
    void *x;
    int y;
} t_object;

t_object *t_object_ctor()
{
    t_object *object = malloc(sizeof(t_object));

    object->s = 0;
    object->x = NULL;
    object->y = 0;

    return object;
}

t_objects *t_objects_ctor()
{
    t_objects *objects = malloc(sizeof(t_objects));

    objects->size = 0;
    objects->y = 0;
    objects->x = 0;
    objects->x_size = malloc(sizeof(size_t) * RESONABLENUMBER);
    objects->v = malloc(sizeof(void *) * RESONABLENUMBER);
    for (int i = 0; i < RESONABLENUMBER; ++i) {
        ((t_object **)objects->v)[i] = t_object_ctor();
    }
    objects->b_size = 0;
    objects->b = NULL;

    return objects;
}

int main()
{
    t_objects_ctor();
    return 0;
}

answered Apr 3, 2022 at 8:33

dulngix

4242 silver badges5 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

cediwelli Over a year ago

If you declare void* v as t_object** v you wouldn't need to make the big cast in the for-loop

Bitter Over a year ago

this seems to work as i intended, thanks

Bitter Over a year ago

if i declare t_object* v as t_object** v it does break and does not compile

Collectives™ on Stack Overflow

How do i assign pointer value inside array of pointers

1 Answer 1

Try this:

Full code like this:

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Try this:

Full code like this:

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related