All In

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

void psn(lst *head, FILE *fp) //b)
{
    if (head == NULL)
    {
        printf("The list is empty");
        return;
    }

    int err = 0;
    while (head != NULL)
    {
        if (err = fprintf(fp, "%s\n", head->data.name) != 1)
            printf("Greshka pri zapis\n");

        if (err = fprintf(fp, "%d\n", head->data.num) != 1)
            printf("Greshka pri zapis\n");

        if (err = fprintf(fp, "%f\n", head->data.cht) != 1)
            printf("Greshka pri zapis\n");

        head = head->next;
    }

    if (fp)
        fclose(fp);
}

int ct(lst *head) //в)
{
    if (head == NULL)
    {
        printf("The list is empty");
        return;
    }
    int countOfNode = 0;

    while (head != NULL)
    {
        if (head->data.num < 10)
        {
            countOfNode++;
        }
        head = head->next;
    }
    return countOfNode;
}

int main()
{
    lst *head = NULL;
    int countNodes;

    countNodes = ct(head);
    printf("Broq na vuzlite: %d", countNodes);

    char fileName[64];
    printf("Vuvedete ime na faila za zapis: ");
    scanf("%63s", fileName);

    FILE *fp = fopen(fileName, "wt");
    if (fp == NULL)
    {
        printf("Greshka pri otvarqne");
        return;
    }

    psn(head, fp); //записваме списъка във файл

    return 0;
}