I need to help for rebuild my cod for arbitraty file access. Cause i dint know what to do, and didnt understand what difference between them. And need to rebuild it for my study. My cod below:

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

struct Person {
    int id;
    char name[50];
    char surname[50];
    char fatherName[50];
    int birthYear;
};

void createFile() {
    struct Person person;
    FILE *file = fopen("data.txt", "r");
    if (file != NULL) {
        fseek(file, 0, SEEK_END);
        long file_size = ftell(file);
        fclose(file);
        if (file_size > 0) {
            printf("File is not empty. Cannot create file.n");
            return;
        }
    }

    file = fopen("data.txt", "w");
    if (file == NULL) {
        printf("Error creating filen");
        return;
    }
    fclose(file);

    printf("File created successfullyn");
    printf("Enter the identification number: ");
    scanf("%d", &person.id);
    printf("Enter the surname: ");
    scanf("%s", person.surname);
    printf("Enter the name: ");
    scanf("%s", person.name);
    printf("Enter the father's name: ");
    scanf("%s", person.fatherName);
    printf("Enter the birth year: ");
    scanf("%d", &person.birthYear);

    file = fopen("data.txt", "a");
    fprintf(file, "%d %s %s %s %dn", person.id, person.surname, person.name, person.fatherName, person.birthYear);
    fclose(file);

    printf("Information added to the filen");
}

void addPerson() {
    FILE *file = fopen("data.txt", "a");
    if (file == NULL) {
        printf("Error opening filen");
        return;
    }

    struct Person person;
    printf("Enter the ID: ");
    scanf("%d", &person.id);
    printf("Enter the surname: ");
    scanf("%s", person.surname);
    printf("Enter the name: ");
    scanf("%s", person.name);
    printf("Enter the father's name: ");
    scanf("%s", person.fatherName);
    printf("Enter the birth year: ");
    scanf("%d", &person.birthYear);

    fprintf(file, "%d %s %s %s %dn", person.id, person.surname, person.name, person.fatherName, person.birthYear);
    fclose(file);
    printf("Information added to the filen");
}

void displayAll() {
    FILE *file = fopen("data.txt", "r");
    if (file == NULL) {
        printf("Error opening filen");
        return;
    }

    struct Person person;
    while (fscanf(file, "%d %s %s %s %d", &person.id, person.surname, person.name, person.fatherName, &person.birthYear) != EOF) {
        printf("ID: %dn", person.id);
        printf("Surname: %sn", person.surname);
        printf("Name: %sn", person.name);
        printf("Father's Name: %sn", person.fatherName);
        printf("Birth Year: %dn", person.birthYear);
        printf("------------------------n");
    }

    fclose(file);
}

void searchPerson() {
    FILE *file = fopen("data.txt", "r");
    if (file == NULL) {
        printf("Error opening filen");
        return;
    }

    int searchId;
    printf("Enter the ID to search: ");
    scanf("%d", &searchId);

    struct Person person;
    int found = 0;
    while (fscanf(file, "%d %s %s %s %d", &person.id, person.surname, person.name, person.fatherName, &person.birthYear) != EOF) {
        if (person.id == searchId) {
            printf("ID: %dn", person.id);
            printf("Surname: %sn", person.surname);
            printf("Name: %sn", person.name);
            printf("Father's Name: %sn", person.fatherName);
            printf("Birth Year: %dn", person.birthYear);
            printf("------------------------n");
            found = 1;
            break;
        }
    }

    if (!found) {
        printf("Information not foundn");
    }

    fclose(file);
}

void deletePerson() {
    FILE *file = fopen("data.txt", "r");
    if (file == NULL) {
        printf("Error opening filen");
        return;
    }

    int deleteId;
    printf("Enter the ID to delete: ");
    scanf("%d", &deleteId);

    FILE *tempFile = fopen("temp.txt", "w");
    if (tempFile == NULL) {
        printf("Error creating temporary filen");
        fclose(file);
        return;
    }

    struct Person person;
    int deleted = 0;
    while (fscanf(file, "%d %s %s %s %d", &person.id, person.surname, person.name, person.fatherName, &person.birthYear) != EOF) {
        if (person.id != deleteId) {
            fprintf(tempFile, "%d %s %s %s %dn", person.id, person.surname, person.name, person.fatherName, person.birthYear);
        } else {
            deleted = 1;
        }
    }

    fclose(file);
    fclose(tempFile);

    if (deleted) {
        remove("data.txt");
        rename("temp.txt", "data.txt");
        printf("Information deleted from the filen");
    } else {
        remove("temp.txt");
        printf("Information not foundn");
    }
}

int main() {
    int choice;

    do {
        printf("Menu:n");
        printf("1) Create file and enter informationn");
        printf("2) Display all informationn");
        printf("3) Search information by key fieldn");
        printf("4) Add information to the filen");
        printf("5) Delete information from the filen");
        printf("6) Exit the programn");
        printf("Choose an option: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                createFile();
                break;
            case 2:
                displayAll();
                break;
            case 3:
                searchPerson();
                break;
            case 4:
                addPerson();
                break;
            case 5:
                deletePerson();
                break;
            case 6:
                printf("Goodbye!n");
                break;
            default:
                printf("Invalid choice. Please try again.n");
                break;
        }
    } while (choice != 6);

    return 0;
}

I tried ask ChatGPT for explain me that, but i and still didn’t understand after that. I tried some changes in search function, but they broke all programm.