Thread: writing to a binary file

Im writing to a Binary file. Having real difficulty. Not sure if I'm on the right track. Here is my code.

Code:

// Project 2.c : Defines the entry point for the console application.
//

#include "stdafx.h"

#include <stdio.h>

#include <stdlib.h>

#include <conio.h>

 

// ------------------- New types declared - Global types.-------------------

struct addr

{

      char first_name[30];

      char surname[40];

      char address1[40];

      char county[50];

      char country[30];

      int  sex;              // 1 for female, 0 for male

      int  active_member;

      int  member_num;

      int  end;          // 1 for yes, 0 for no

};

 

//------------------ Global Variables -------------------------

FILE *fp;

 

// ----------------- Function prototypes ----------------------

 

int main(void);

void details(struct addr *, int); // Using pass by reference for structure.

void display_details(struct addr); // Display details on screen

void store_details(struct addr);  // Stores structure to disk

void retrieve_details(struct addr *, int);

 

// ------------------------------------------------------------

 

int main(void)

{

      struct addr member_details[100];                // Declare variable to use.

      struct addr disk_details;

      int i;

 

    // Open file for writing - create file or blank it.

	  if((fp = fopen("store.bin","wb")) == NULL)

      {

            printf("Cannot open file \"store.bin\" for writing.....\n");

            exit(1);

      }

 

      for (i = 0; i <= 100; i++)      // Limited to 100 members for the time being.

      {

            details(&member_details[i], i);   // Function call

            store_details(member_details[i]);

      }

     

      for (i=0; i<=100; i++)

      {

            printf("Member number %d details:\n", i+1);

            retrieve_details(&disk_details, i);

            display_details(member_details[i]);

      }

 

     

fclose(fp);

}

 

/* -----------------------------------------------------------------

      Function to get and store the details of each member.

      Called:      details(struct addr *);

      IN:         struct addr *: Address  of structure addr to store details in.

                  int : member number;

      OUT:      Filled structure.

 ---------------------------------------------------------------- */

 

void details(struct addr *member, int i)

{

      //int i;

      printf("Enter first name for member %d: ", i);

      scanf("%s", member->first_name);

 

      printf("Enter surname for member %d: ", i);

      scanf("%s", member->surname);

 

      printf("Enter the first line of address for member %d: ", i);

      scanf("%s", member->address1);

           

      printf("Enter county for member %d: ", i);

      scanf("%s", member->county);

                 

      printf("Enter country for member %d: ", i);

      scanf("%s", member->country);

                 

      printf("Is member %d active (1=Y/0=N): ", i);

      scanf("%d", &member->active_member);

           

      printf("Is member %d male or female (1=Y/0=N): ", i);

      scanf("%d", &member->sex);

 

      printf("End\? (1=Y/0=N); ");

      scanf("%d",&member->end);

      member->member_num = i;

 

      printf("\n\n");

}

 

void display_details(struct addr member)

{

      printf("\tFirst name = %s\n", member.first_name);

      printf("\tSurname = %s\n", member.surname);

      printf("\tAddress line 1 = %s\n", member.address1);

      printf("\tCounty = %s\n", member.county);

      printf("\tCountry = %s\n", member.country);

      printf("\n\n");

 

}

 

 

void store_details(struct addr member)

{

      fseek(fp, 0, SEEK_END);

            // Write structure to file.

 

     

      fwrite(&member, sizeof(struct addr), 1, fp);

}

 

 

void retrieve_details(struct addr *member, int num)

 

{

      fseek(fp, (num * sizeof(struct addr)), SEEK_SET);

 

      fread(member, sizeof(struct addr), 1, fp);

 

}

for (i=0; i<=100; i++)

goes from 0-100, meaning 101 elements.