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

struct Student
{
    char *name;
    int fac_num;
    double avg_grade;
};

typedef struct Student Student_t;

struct StudentList
{
    Student_t student;
    struct StudentList *next;
};

typedef struct StudentList StudentList_t;


void delete_all(StudentList_t **head)
{
    StudentList_t *temp;
    while(*head) {
        temp = *head;
        *head = (*head)->next;
        free(temp);
    }

    *head = NULL;
}

StudentList_t* read_from_binary(StudentList_t *head, FILE *fp)
{
    Student_t student;
    StudentList_t *current;
    int res;
    while(1) {
        res = fread(&student, 1, sizeof(Student_t), fp);
        if(res < 1) {
            break;
        }

        if(head == NULL) {
            head = malloc(sizeof(StudentList_t));
            head->student = student;
            current = head;
        } else {
            current->next = malloc(sizeof(StudentList_t));
            current->next->student = student;
            current = current->next;
        }
    }

    return head;
}

double get_avg_grade(StudentList_t *head)
{
    double avg = 0;
    int count = 0;
    while(head) {
        avg += head->student.avg_grade;
        count += 1;
        head = head->next;
    }

    if(count > 0) {
        avg = avg / count;
    } else {
        avg = 0;
    }

    return avg;
}

void write_to_bin_file(StudentList_t *head, char* file_name)
{
    FILE *fp = fopen(file_name, "wb");
    if(fp == NULL) {
        perror("Cannot open file");
        exit(EXIT_FAILURE);
    }

    while(head) {
        fwrite(&head->student, 1, sizeof(Student_t), fp);
        head = head->next;
    }

    fclose(fp);
}

void insert_student(StudentList_t **head, Student_t student)
{
    StudentList_t *temp;
    if(*head == NULL) {
        *head = malloc(sizeof(StudentList_t));
        (*head)->student = student;
        (*head)->next = NULL;
    } else {
        temp = malloc(sizeof(StudentList_t));
        temp->next = *head;
        *head = temp;
    }
}

int main () {
    return 0;
}