RZLab2(files)

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

#define HEADOUTFORMAT "%-15s%-15s%-15s%-15s%-10s\n"
#define OUTFORMAT "%-15s%-15s%-15s%-15d%-10.3f\n"

typedef struct {
    char firstName[64], lastName[64], education[64];
    int bYear;
    float salary;
} person;

void print(person *persons, int n);

int input(person **persons)
{
    int n, i;
    FILE *file = fopen("input.bin", "wb");
    if (!file) { printf("File open error"); _getch(); return 0; }

    printf("input n: "); scanf("%d", &n);
    *persons = (person*) malloc(sizeof(person) *n);

    printf("Input persons (by format - FirstName LastName Education BirthYear Salary):\n");
    for (i = 0; i < n; i++)
    {
        person *p = *persons;
        scanf("%s %s %s %d %f", p[i].firstName, p[i].lastName, p[i].education, &p[i].bYear, &p[i].salary);
    }
    fclose(file);
    file = fopen("input.bin", "ab");
    //fwrite(*persons, sizeof(person), n, file);
    for (i = 0; i < n; i++)
    {
        fwrite(&(*persons)[i], sizeof(person), 1, file);
    }

    fclose(file);
    return n;
}

person* read(int count)
{
    int i = 0;
    FILE *file;
    person *persons = NULL;
    file = fopen("input.bin", "rb");

    if (!file) { printf("File open error"); _getch(); return 0; }

    persons = (person*) malloc(sizeof(person) *count);
    //if (fread(&persons, sizeof(person), count, file) == 0) return NULL;
    while (!feof(file))
    {
        fread(&persons[i], sizeof(person), 1, file);
        i++;
    }


    fclose(file);
    return persons;
}


void print(person* persons, int n)
{
    int i = 0;
    FILE *file = fopen("output.txt", "w");
    if (!file) { printf("File open error"); _getch(); return 0; }

    if (!persons) return;
    putchar('\n'); printf(HEADOUTFORMAT, "Name", "Surname", "Education", "Birth Year", "Salary");
    fprintf(file, HEADOUTFORMAT, "Name", "Surname", "Education", "Birth Year", "Salary");
    for (i = 0; i < n; i++)
    {
        printf(OUTFORMAT, persons[i].firstName, persons[i].lastName, persons[i].education, persons[i].bYear, persons[i].salary);
        fprintf(file, OUTFORMAT, persons[i].firstName, persons[i].lastName, persons[i].education, persons[i].bYear, persons[i].salary);
    }

    fclose(file);
}


int age(person *persons, int n, int dage, int uage)
{
    int i = 0, c = 0;
    time_t t = time(NULL);
    struct tm *now = localtime(&t);
    FILE *file = fopen("ageout.txt", "w");
    if (!file) { printf("File open error"); _getch(); return 0; }

    if (!persons) return -1;
    putchar('\n'); printf(HEADOUTFORMAT, "Name", "Surname", "Education", "Birth Year", "Salary");
    fprintf(file, HEADOUTFORMAT, "Name", "Surname", "Education", "Birth Year", "Salary");
    for (i = 0; i < n; i++)
        if (now->tm_year + 1900 - persons[i].bYear >= dage && now->tm_year + 1900 - persons[i].bYear <= uage)
        {
            printf(OUTFORMAT, persons[i].firstName, persons[i].lastName, persons[i].education, persons[i].bYear, persons[i].salary);
            fprintf(file, OUTFORMAT, persons[i].firstName, persons[i].lastName, persons[i].education, persons[i].bYear, persons[i].salary);
            c++;
        }

    fclose(file);
    return c;
}

person *psort(person *p, int n)
{
    int i, j; person tmp;
    for (i = 0; i < n; i++)
    {
        for (j = i + 1; j < n; j++)
        {
            if (strcmp(p[i].lastName, p[j].lastName) > 0)
            {
                tmp = p[i];
                p[i] = p[j];
                p[j] = tmp;
            }
        }
    }

    return p;
}

int main()
{
    int n = 1, minage, maxage;
    person *p = NULL;
    printf("Input lower age limit: ");
    scanf("%d", &minage);
    printf("Input upper age limit: ");
    scanf("%d", &maxage);

    n = input(&p);
    printf("\nAgeFunc:");
    age(p, n, minage, maxage);
    p = read(n);
    p = psort(p, n);
    printf("\nSortFunc:");
    print(p, n);

    _getch();
    return 0;
}

/*Ввести з клавіатури масив з N записів. Кожен запис повинен містити такі поля: прізвище,
ім'я, рік народження,   освіта, зарплата. Вивести масив на  екран, впорядкувавши рядки   таблиці  за
прізвищами. Обчислити кількість осіб з таблиці віком від 20 до 40 років.*/