assign a nested structure pointer to a nested structure - c

Question

I've one solid structure and another structure with pointers. The purpose of program is to assign: solid structure to structure with pointers and access each solid structure member using other structure pointer.
I've problem statement: as two structure member as not symmetric, when i assign solid structure address to structure with pointers, member pointer initialization go bad and crash the system.
Does anyone have any approach to find a solution for this problem in an optimized way?
----------------------------------------------------------------------- program -----------------------------
#include <stdio.h>
#include <string.h>
#include <stddef.h>
/* ===================== Binding Structure ================================= */
typedef struct
{
char id;
}tmodel;
typedef struct
{
char id;
}tbrand;
typedef struct
{
char id;
}tcommercialRef;
typedef struct
{
char id;
}tserialnum;
typedef struct
{
tmodel *smodel;
tbrand *sbrand;
tcommercialRef *scommref;
tserialnum *sslnum;
}tmetadata;
typedef struct
{
tmetadata *smetadata;
}tlink;
typedef struct
{
tlink *slink;
}trefernce;
typedef struct
{
char id[10];
int ttl;
int tss;
trefernce *sref;
}telectrical;
/* ===================== Application Strucuture ==============================*/
void filldata(telectrical *elec);
typedef struct
{
tmodel smodel;
tbrand sbrand;
tcommercialRef scommref;
tserialnum sslnum;
}Ymetadata;
typedef struct
{
Ymetadata smetadata;
}slink;
typedef struct
{
slink glink;
}refernce;
typedef struct
{
char id[10];
int ttl;
int tss;
refernce grefernce;
}gtelectrical;
//solid strucutre object
gtelectrical obj;
//structure pointer object
telectrical *elec = {0};
/* =============================== main.c =================================== */
int main()
{
printf("test");
//static void **p = (void *)&elec;
obj.tss = 55;
obj.ttl = 100;
obj.grefernce.glink.smetadata.smodel.id = 5;
obj.grefernce.glink.smetadata.sbrand.id = 6;
obj.grefernce.glink.smetadata.scommref.id = 7;
obj.grefernce.glink.smetadata.sslnum.id = 8;
elec = (telectrical *)&obj;
//elec structure -> sref pointer goes bad as it's not same type as "grefernce"
//*p = (void *)&obj;
//static long x = (long) offsetof( telectrical, sref);
//(long) offsetof(struct telectrical, sref);
//*(*p + x) = obj.grefernce.glink.smetadata.;
elec->id[0] = 0;
elec->id[1] = 1;
elec->id[2] = 2;
elec->ttl = 5;
elec->tss = 10;
elec->sref->slink->smetadata->sslnum->id = 4;
elec->sref->slink->smetadata->sbrand->id = 1;
elec->sref->slink->smetadata->scommref->id = 2;
elec->sref->slink->smetadata->smodel->id = 3;
//filldata(elec);
printf("------");
printf("%d\n",elec->sref->slink->smetadata->sslnum->id);
printf("%d\n",elec->sref->slink->smetadata->sbrand->id);
printf("%d\n",elec->sref->slink->smetadata->scommref->id);
printf("%d\n",elec->sref->slink->smetadata->smodel->id);
return 0;
}
/* //////////////////////////////////////// user scope ////////////////////////////// */
void filldata(telectrical *pelec)
{
pelec->id[0] = 0;
pelec->id[1] = 1;
pelec->id[2] = 2;
pelec->ttl = 5;
pelec->tss = 10;
//pelec->sref->slink->smetadata->sslnum->id = 4;
//pelec->sref->slink->smetadata->sbrand->id = 1;
//pelec->sref->slink->smetadata->scommref->id = 2;
//pelec->sref->slink->smetadata->smodel->id = 3;
}

Answer 1

You are not assigning memory for the pointers to other struct present inside another struct. Here is something which might help you in multi-level memory allocation and assignment:
#include<stdio.h>
#include<stdlib.h>
typedef struct A
{
int i;
}A_Node;
typedef struct B
{
A_Node *A_ptr;
}B_Node;
typedef struct C
{
B_Node *B_ptr;
}C_Node;
int main(void)
{
//ACCESSING-MANIPULATING A USING B
B_Node B_obj;
B_obj.A_ptr=malloc(sizeof(*(B_obj.A_ptr)));
(B_obj.A_ptr)->i=192;
A_Node A_obj=*(B_obj.A_ptr); //For checking if the allocation is successful and good
printf("%d\n",A_obj.i);
//ACCESSING-MANIPULATING A USING C
C_Node C_obj;
C_obj.B_ptr=malloc(sizeof(*(C_obj.B_ptr))); //allocating space for struct of B using C object
(C_obj.B_ptr)->A_ptr = malloc(sizeof(*((C_obj.B_ptr)->A_ptr))); //allocating space for struct of A using B Struct for which space was allocated in previous step by C struct
((C_obj.B_ptr)->A_ptr)->i=876;
A_obj=*((C_obj.B_ptr)->A_ptr); //For checking if the allocation is successful and good
printf("%d\n",A_obj.i);
return 0;
}
Read the code and ask if there are any doubts, in the similar way this multi-level struct-inside-struct can be created (though it would be ugly).