Need logic to allocate memory for nested structures - data-structures

Question

I am not able to allocate memory for nested structures using pointers.
What syntax should I use to allocate the memory for lots of structures that have pointers to other structures? How should I go about accessing the values in the structures once the memory is allocated?
struct A {
int *a;
struct B *b;
};
struct B {
int *b;
struct C *c;
};
struct C {
int *c;
struct D *d;
};
struct D {
int *d;
};
int main(int argc, const char* argv[]) {
struct A* foo;
/* Structure allocation */
/* use of structures */
}
I can't go beyond 2 nested structures. Beyond that I start getting Segmentation fault.
I tried something like this:
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
typedef struct file f1;
typedef struct command c1;
typedef struct arguments a1;
typedef struct ccity ccity;
typedef struct csub csub;
struct arguments {
char *argname;
struct arguments *next;
};
struct command {
char *cmdname;
struct arguments *args;
};
struct file{
int fileid;
char *filename;
struct command *cmd;
};
struct sub{
char *subname;
};
struct city {
char *city_name;
struct sub *s11;
};
struct road{
char *name;
struct city *next_city;
};
int main()
{
char name[] = "HELLO ";
struct file *f1;
struct city *c1 = NULL;
struct road *r1 = NULL;
struct sub *s1 = NULL;
printf("HELOOOOOOOOO");
f1->filename;
f1 = malloc(10*sizeof(struct file ));
f1->filename = (char *)malloc(10*sizeof(char *));
c1 = malloc(sizeof(c1));
r1 = malloc(sizeof(r1));
s1 = malloc(sizeof(s1));
r1->name = malloc(100*sizeof(char *));
r1->next_city = malloc(100*sizeof(r1->next_city));
c1->city_name = malloc(100*sizeof(char *));
c1->s11 = malloc(100*sizeof(c1->s11));
c1->s11->subname = calloc(120,sizeof(char*));
(*c1).s11->subname = "text";
(*r1).next_city->s11->subname =
malloc(10 * sizeof((*r1).next_city->s11->subname));
strncpy((*r1).next_city->s11->subname,"sant",4);
r1->name = malloc(sizeof(char *));
c1->city_name = malloc(sizeof(char *));
r1->next_city = malloc(sizeof(char *));
r1->next_city->city_name = "Hello";
/*strcpy(f1->filename,"file1");
printf("name is %s\n",(f1->filename));
c1->cmdname = (char *)malloc(10*sizeof(c1->cmdname));
strcpy(f1[0].cmd[0].cmdname,"command1");
printf("name is %s\n",f1[0].cmd[0].cmdname);
strcpy(f1[0].cmd[1].cmdname,"command2");
printf("name is %s\n",f1[0].cmd[1].cmdname);
strcpy(f1[0].cmd[2].cmdname,"command3");
printf("name is %s\n",f1[0].cmd[2].cmdname);
strcpy(f1[0].cmd[2].args[0].argname,"argument1");
printf("name is %s\n",f1[0].cmd[2].args[0].argname);
strcpy(f1[0].cmd[2].args[0].argname,"argument1");
printf("name is %s\n",f1[0].cmd[2].args[1].argname);
(f1[0].cmd[0].args[0]).argname = malloc(20*sizeof(char*));
strcpy((f1[0].cmd[0].args[0]).argname,"argument1");
printf("name is %s\n",(f1[0].cmd[0].args[0]).argname);
*/
}