Thread: Pointer and Struct ???

This is the include file test.h

Code:

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>

struct _address
{
	char *Street;
	int HouseNumber;
} ;

struct _name
{
	int age;
	char *lastname, *firstname;
	struct _address *addr;
} ;

struct _student
{
	int num;
	struct _name *NameOfStudent;
} ;

This is the write.c code to write data into binary file:

Code:

#include "test.h"
int main()
{
	FILE *f;
        struct _student *hs1, *hs;
	hs1 = (struct _student *)malloc(sizeof(struct _student));
	hs1->NameOfStudent = (struct _name*)malloc(sizeof(struct _name));
	hs1->NameOfStudent->addr = (struct _address*)malloc(sizeof(struct _address));
	hs1->NameOfStudent->lastname = "John";
	hs1->NameOfStudent->firstname = "A";
	hs1->NameOfStudent->age = 15;
	hs1->NameOfStudent->addr->Street = " London  ";
	hs1->NameOfStudent->addr->HouseNumber = 123;
	hs1->num = 1;

	printf(" -------------  Input ----------------\n");
	printf(" %d %s %s %d %s  \n", 
			hs1->num, hs1->NameOfStudent->lastname, 
			hs1->NameOfStudent->firstname, 
			hs1->NameOfStudent->addr->HouseNumber, 
			hs1->NameOfStudent->addr->Street);
	f = fopen ("/root/test","wb");
		fwrite((struct _student *)hs1, sizeof(struct _student), 1, f);
		fwrite((struct _name *)hs1->NameOfStudent, sizeof(struct _name), 1, f);
		fwrite((struct _address *)hs1->NameOfStudent->addr, sizeof(struct _address), 1, f);
	fclose(f);


	free(hs1->NameOfStudent->addr);
	free(hs1->NameOfStudent);
	free(hs1);

	return 0;
}

This is the read.c code to read from binary file

Code:

#include "test.h"

struct _student STUDENT;
struct _address ADDRESS;
struct _name NAME;

int main()
{
	FILE *f;
	struct _student *hsRead;	
	struct _name *name;
	struct _address *addr;
	hsRead = &STUDENT;
	name = &NAME;
	addr =  &ADDRESS;
	printf(" sizeof(struct _student) = %d \n", sizeof(struct _student));
	printf(" sizeof(struct _name) = %d \n", sizeof(struct _name));
	printf(" sizeof(struct _address) = %d \n", sizeof(struct _address));
	printf(" -------------  Readfile ----------------\n");
	//hs = (struct _student *)malloc(sizeof(struct _student));
	f = fopen ("/root/test","rb");
	while(!feof(f))
	{
		int status = fread((struct _student *)hsRead, sizeof(struct _student)+sizeof(struct _name)+sizeof(struct _address), 1, f);
		if (status > 0)
		{
			name = hsRead->NameOfStudent;
			addr = hsRead->NameOfStudent->addr;
			printf(" STT : %d \n", hsRead->num);
			printf(" NAME : %s %s \n",  name->lastname, name->firstname);
			printf(" AGE(s) : %d \n", name->age);
			printf(" ADDR : %d %s  \n",  addr->HouseNumber, addr->Street);
		}
	}
	fclose(f);
	return 0;
}

The result of read.c is

Code:

 sizeof(struct _student) = 8
 sizeof(struct _name) = 16
 sizeof(struct _address) = 8
 -------------  Readfile ----------------
 STT : 1
 NAME : (null) (null)
 AGE(s) : 0
Segmentation fault (core dumped)

Why the result of NAME show here is (null) (null) and AGE(s) is 0 and the Segmentation fault ??? When I write the code WRITE and READ in ONE C file, it's ok. How can i fix it ??? Please help me. I'm a newbie in C on Linux.
Thanks.

oh yeah, you declared pointers but didnt allocate space for them using malloc...

and is his fwrite implementation correct??