برنامه نویسی - مثال کلاسی کار با ساختار

این مثال دو بخش دارد، یکی ایجاد پایگاه داده از اطلاعات کتابها و نوشتن آنها در فایل باینری book_data.db و بخش دوم شامل خواندن اطلاعات از همین فایل و نمایش آنها. ویدیوی ضبط شده مربوط به این مثال در پست بعدی منتشر می شود.

#include "stdafx.h"
#include <iostream>

struct BookInfo
{
	char name[30];
	char author[30];
	int  nPage;
	float price;
	int year;
};

void CreateDatabase()
{
	printf("To start, enter number of books you want to store in the database\n");
	int n = 0;
	scanf_s("%d", &n);
	printf("Please enter Book information for %d books as follows\n", n);
	printf("Name, Author, Pages, Price, Year of Publication\n");

	BookInfo *books = new BookInfo[n];
	for (int i = 0; i < n; i++)
	{
		std::cin.ignore();
		printf("\n#%d Name: ", i + 1);
		gets_s(books[i].name, 30);
		printf("\n#%d Author: ", i + 1);
		gets_s(books[i].author, 30);
		printf("\n#%d Pages: ", i + 1);
		scanf_s("%d", &books[i].nPage);
		printf("\n#%d Price: ", i + 1);
		scanf_s("%f", &books[i].price);
		printf("\n#%d Year: ", i + 1);
		scanf_s("%d", &books[i].year);
	}
	FILE* fp = 0;
	fopen_s(&fp, "book_data.db", "wb");
	if (!fp)
	{
		printf("File can't be oppened.\n");
		return;
	}

	fwrite(books, sizeof(BookInfo), n, fp);
	fclose(fp);

	printf("Data saved successfully\n");
}

void ReadDatabase()
{
	int n = 2;

	BookInfo *books = new BookInfo[n];

	FILE* fp = 0;
	fopen_s(&fp, "book_data.db", "rb");
	if (!fp)
	{
		printf("File can't be oppened.\n");
		return;
	}

	fread(books, sizeof(BookInfo), n, fp);
	for (int i = 0; i < n; i++)
	{
		printf("\n#%d Name: %s", i + 1, books[i].name);

		printf("\n#%d Author: %s", i + 1, books[i].author);

		printf("\n#%d Pages: %d", i + 1, books[i].nPage);

		printf("\n#%d Price: %.1f", i + 1, books[i].price);

		printf("\n#%d Year: %d", i + 1, books[i].year);

		printf("\n--------------------------------------------");
	}

	fclose(fp);
	delete[] books;
}

int main()
{
	printf("Welcome to Book Database Application:\n");
	bool create_data = false; //change to false for read mode

	if (create_data)
		CreateDatabase();
	else
		ReadDatabase();

	getchar();
    return 0;
}