void main()
{
	date *arr;
	lecturer *data;
	lecturer **courses;
	int size, i, j;

	printf("enter number of lecturers: ");
	scanf("%d", &size);

	//arr = (date*)calloc(size, sizeof(date));
	data = (lecturer*)calloc(size, sizeof(lecturer));
	courses = (lecturer**)calloc(20, sizeof(lecturer*));

	for (i = 0; i < size; i++)
	{

		printf("enter name of lectrur %d: ", i + 1);
		data[i].name = (lecturer*)calloc(20, sizeof(lecturer));
		scanf("%s", data[i].name);

		printf("enter lecturer birthdate: \n");
		scanf("%d %d %d", &data[i].birthdate.day, &data[i].birthdate.month, &data[i].birthdate.year);

		printf("enter number of courses of %s: ", data[i].name);
		scanf("%d", &data[i].num_of_courses);

		for (j = 0; j < data[i].num_of_courses; j++)
		{
			printf("enter name of course %d: ", j + 1);
			data[i].courses = (lecturer*)calloc(20, sizeof(lecturer));
			scanf("%s", data[i].courses);
		}
	}


}