[Lập trình C] Bài tập lập trình C 3

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

typedef struct {
	char name[28];
	char category[25];
	int price;
	int year;
} book_st;

void inputData(book_st arr[3])
{
	int i;
	for(i = 0; i < 3; i++) {
		printf("\nEnter data of book %d:\n", i + 1);
		printf("+ Name: ");
		gets(arr[i].name);
		printf("+ Category: ");
		gets(arr[i].category);
		printf("+ Price: ");
		scanf("%d", &arr[i].price);
		printf("+ Year: ");
		scanf("%d", &arr[i].year);
		fflush(stdin);
	}
}

void displayHeader()
{
	printf("\n");
	printf("%-3s||", "No");
	printf("%-28s||", "Name");
	printf("%-25s||", "Category");
	printf("%-8s||", "Price");
	printf("%-4s||", "Year");
	printf("\n");
}

void displayRow(book_st arr[3], int index)
{
	printf("%03d||", index + 1);
	printf("%-28s||", arr[index].name);
	printf("%-25s||", arr[index].category);
	printf("%-8d||", arr[index].price);
	printf("%-4d||\n", arr[index].year);
}

void swap(book_st *book1, book_st *book2)
{
	book_st temp = *book1;
	*book1 = *book2;
	*book2 = temp;
}

void sortDisplay(book_st arr[3])
{
	// Sort a-z
	int i, j;
	for (i = 0; i < 2; i++) {
		for (j = i + 1; j < 3; j++) {
			if(strcmp(arr[i].category, arr[j].category) > 0) {
				swap(&arr[i], &arr[j]);
			} else if(strcmp(arr[i].category, arr[j].category) == 0) {
				if (arr[i].price > arr[j].price) {
					swap(&arr[i], &arr[j]);
				}
			}
		}
	}

	// Print table
	displayHeader();
	for(i = 0; i < 3; i++) {
		displayRow(arr, i);
	}
	
	// Find min year, max year
	int minYear = arr[0].year, maxYear = arr[0].year;
	for(i = 1; i < 3; i++) {
		if (arr[i].year < minYear) minYear = arr[i].year;
		if (arr[i].year > maxYear) maxYear = arr[i].year;
	}
	// Count statistic
	int* statistic = (int*)calloc(maxYear + 1, sizeof(int));
	for(i = 0; i < 3; i++) {
		int yearValue = arr[i].year;
		statistic[yearValue] += 1;
	}
	// Print statistic
	printf("\n");
	for(i = minYear; i <= maxYear; i++) {
		if (statistic[i] == 1) {
			printf("The year of %d has %d book\n", i, statistic[i]);
		}
		else if (statistic[i] > 1) {
			printf("The year of %d has %d books\n", i, statistic[i]);
		}
	}
	printf("\n");
	free(statistic);
}

void searchDisplay(book_st arr[3])
{
	// Nhap tu ban phim
	char category[10];
	printf("\nEnter category for search : ");
	gets(category);
	printf("\n");

	// Tim kiem
	int i = 0, count = 0;
	for (i = 0; i < 3; i++) {
		if (strcmp(arr[i].category, category) == 0) {
			displayRow(arr, i);
			count++;
		}
	}
	if (count == 0) {
		printf("\nThere are no book of this category\n");
	}
}

void saveToFile(book_st *p)
{
	FILE *fp = fopen("book.dat", "wb");

	int i;
	for (i = 0; i < 3; i++) {
		fwrite(p + i, sizeof(book_st), 1, fp);
	}

	fclose(fp);
}

int main()
{
	book_st bookList[3];
	int entry;

	while(1) {
		// Menu
		printf("\n");
		printf("1. Input data of book\n");
		printf("2. Sort, display details information and statistic of all books\n");
		printf("3. Find the book of category\n");
		printf("4. Save to binary file book.dat\n");
		printf("5. Exit\n");

		// Nhap 1 so tuong ung voi menu:
		printf("\nEnter a number from 1 to 5: ");
		while(1) {
			if(!scanf("%d", &entry) || entry < 1 || entry > 5) {
				fflush(stdin);
				printf("Enter a number from 1 to 5: ");
			} else {
				fflush(stdin);
				break;
			}
		}

		// Xu ly lua chon
		if (entry == 1) {
			inputData(bookList);
		} else if (entry == 2) {
			sortDisplay(bookList);
		} else if (entry == 3) {
			searchDisplay(bookList);
		} else if (entry == 4) {
			saveToFile(bookList);
		} else {
			break;
		}
	}

	return 0;
}