Thread: Regarding File IO

Hmmm, I have a phonebook program but, I don't know how to store my previously recorded entries so that whenever I open my phonebook again the previously recorded files are still there for access.

Replies will be highly appreciated

Thanks in advance!!

FILE IO and Linked Lists are the topic of this activity.

First you should post your attempt.Then the story goes on

Code:

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


typedef struct phonebook {
    char name[30];
    char tel[15];
    int age;
    struct phonebook *next;
} phonebook_t;


void AddEntry (void); 
void DeleteEntry (void);
void SearchEntry (void);   
void ListAll(void);
void writePCText(void);


phonebook_t *head= NULL;


int main() {
    
    int choice;


    while (choice!=5) {
    printf("\nWelcome to PHONEBOOK MENU:\n\n");
    printf("> [1] Add Entry\n");
    printf("> [2] Delete Entry\n");
    printf("> [3] Search for Entry\n");
    printf("> [4] Show all Entries\n");
    printf("> [5] Exit\n\n");
    printf("ENTER CHOICE: ");
    scanf("%d",&choice);
        switch (choice) {
            case 1: AddEntry();
            break;
            case 2: DeleteEntry();
            break;
            case 3: SearchEntry();
            break;
            case 4: ListAll();
            break;
            case 5:
                writePCText(); 
                 exit(1);
            break;
           
            default:
                    printf ("Invalid INPUT!\n"); 
        }
    
    }
    return 0;
}    


void AddEntry (void){
    phonebook_t *new_name;
    
    new_name= (phonebook_t *)malloc (sizeof (phonebook_t));
    if (new_name == NULL) {
        printf ("Out of memory!\n");
        exit (-1);
    }
    printf ("\n\nName: ");
    getchar();
    fgets(new_name->name,30,stdin); 
    printf ("Phone Number: ");
    fgets(new_name->tel,15,stdin); 
    printf ("Age (Numerical Value):  ");
    scanf("%d",&new_name->age);
    
    new_name->next= head;
    head= new_name;
}    


void DeleteEntry (void) {
    phonebook_t *del_ptr;   
    phonebook_t *prev_ptr;  
    char del_name[30]; 
    
    printf ("Enter Name to be Deleted:  ");
    getchar();
    fgets(del_name,30,stdin); 
    if (head == NULL) {
        printf ("\nName not registered in the list!\n");
        return;
    }
    if (strcmp(head->name, del_name) == 0) {
       printf("\n%s Deleted!\n",del_name);
        del_ptr = head;
        head = head->next;
        free(del_ptr);
        return; 
    }
    prev_ptr = head;
    while (prev_ptr->next != NULL) {
        if (strcmp(prev_ptr->next->name,del_name) == 0) {
        printf("\n%s Deleted!\n",del_name);
            del_ptr= prev_ptr->next;
            prev_ptr->next= del_ptr->next;
            free(del_ptr);
            return;
        }
        prev_ptr= prev_ptr->next;
    }
    printf ("Name not found in the list!\n");
}


void SearchEntry (void){
    char name[30];  
    phonebook_t *search_ptr;
    printf ("\nSearch for a Name (Exact): ");
    getchar();
     fgets(name,30,stdin); 
    search_ptr= head;
    while (search_ptr != NULL) {
        if (strcmp (search_ptr->name, name) == 0) {  
            printf("\n%sFound!\n",name);
            printf ("Phone Number: %s\n", search_ptr->tel);
            printf ("Age: %d\n", search_ptr->age);
            return;
        }
        search_ptr= search_ptr->next;
    }
    printf ("\nName not registered in the list!\n");
}


  void ListAll(void)
{
    phonebook_t *tmp_ptr;
    printf ("\nAll Names Registered:\n");
    tmp_ptr= head;
    while (tmp_ptr != NULL) {
        printf ("\nName: %s\n",tmp_ptr->name);
        printf ("Phone Number: %s\n",tmp_ptr->tel);
        printf ("Age: %d\n\n\n",tmp_ptr->age);
        tmp_ptr= tmp_ptr->next;
    }
}


void writePCText(void){
      FILE *out;


      out = fopen("hehe.txt", "w" );
      phonebook_t *tmp_ptr;
      tmp_ptr=head;
      while(tmp_ptr!=NULL){
		fprintf(out,"%s" , tmp_ptr->name);
		fprintf(out,"%s", tmp_ptr->tel);
		fprintf(out,"%d", tmp_ptr->age);
		tmp_ptr= tmp_ptr->next;
    }
    
     printf("Thank you! Hope to see you soon!");
     exit(1);
     }

Here is my code )

You already have a function you can use to write to a file ...

Try changing ListAll() to accept a FILE *.
Then either send stdout for listing on the screen, or a pointer to an opened file for listing on that particular file

Code:

void ListAll(FILE *handle) {
    /* ... */
    fprintf(handle, "whatever");
    /* .... */
}

and call it like

Code:

ListAll(stdout);

or

Code:

FILE *h;
h = fopen("whatever", "w");
if (h) {
    ListAll(h);
    fclose(h);
} else /* error */;

--------

Of course you still have to write the function to read from the file.

Thank you very much, I'll also use that but my problem is that I need to save my previous entries so that whenever I open my phonebook again, I can use the delete, search and list function for my previously recorded data.

I can't seem to read the entries from the txt file >.<

What have you tried?

Bye, Andreas