图书管理系统的c实现

用于图书信息的管理。包括图书信息的创建、图书信息的打印、图书信息的查询、图书信息的修改、图书信息的删除。方便用户整理图书，查询图书。

这个图书管理系统是由单链表这一数据结构实现的，板块包括图书信息的创建、打印、查询、修改、删除、以及图书价格的排序等组成。 代码后面也有注释的，基本很好理解的。

下面为源代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//3.数据的设计
	//3.1程序的数据存储--->容器
	//3.2数据的结构 --->图书的信息

struct bookInfo
{
	char name[20];  //书名
	float price;    //书籍的价格
	int num;		//书籍的数量
};

//定义链表
struct Node
{
	struct bookInfo data;
	struct Node* next;
};

struct Node* list = NULL;  //将链表声明成全局变量

//创建表头：表头就是结构体变量
struct Node* createHead()
{
	//动态内存申请
	struct Node* headNode = (struct Node*)malloc(sizeof(struct Node));
	//变量初始化
	headNode->next = NULL;
	return headNode;
}

//创建节点：为插入做准备
	// 把用户的数据变成结构体变量
struct Node* createNode(struct bookInfo data)
{
	struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
	newNode->data = data;
	newNode->next = NULL;
	return newNode;
}

//数据插入（头插法）
void insertNodeByHead(struct Node* headNode, struct bookInfo data)
{
	struct Node* newNode = createNode(data);
	newNode->next = headNode->next;
	headNode->next = newNode;
}

//尾插法
/*struct insertNodeByTall(struct Node* headNode, int data)
{
	struct Node* pMove = headNode;
	while (pMove != NULL)
	{
		pMove = pMove->next;
	}
	struct Node* newNode = createHead(data);
	pMove->next = newNode;
}*/

//指定删除（删除链表中元素）
//posLeftNode->next=posNode->next;
//free(posNode);
void deleteNodeByName(struct Node* headNode, char* bookname)
{
	struct Node* posLeftNode = headNode;
	struct Node* posNode = headNode->next;
	//书籍名字是字符串，字符串比较函数
	while (posNode != NULL && strcmp(posNode->data.name, bookname))
	{
		posLeftNode = posNode;
		posNode = posLeftNode->next;
	}
	//讨论查找的结果
	if (posNode == NULL)
		return;
	else
	{
		printf("删除成功！\n");
		posLeftNode->next = posNode->next;
		free(posNode);
		posNode = NULL;
	}
}
//查找
struct Node* searchByName(struct Node* headNode, char* bookName)
{
	struct Node* posNode = headNode->next;
	while (posNode != NULL && strcmp(posNode->data.name, bookName))
	{
		posNode = posNode->next;
	}
	return posNode;
}

//打印链表
void printList(struct Node* headNode)
{
	struct Node* pMove = headNode->next;
	printf("书名\t价格\t数量\n");
	while (pMove != NULL)
	{
		printf("%s\t%.1f\t%d\n", pMove->data.name, pMove->data.price, pMove->data.num);
		pMove = pMove->next;
	}
}

//直接文件操作
//文件写操作
void saveInfoToFile(const char* filename, struct Node* headNode)
{
	FILE* fp = fopen(filename, "w");
	struct Node* pMove = headNode->next;
	while (pMove != NULL)
	{
		fprintf(fp, "%s\t%.1f\t%d\n", pMove->data.name, pMove->data.price, pMove->data.num);
		pMove = pMove->next;
	}
	fclose(fp);
}

//文件读操作
void readInfoFromFile(const char* fileName, struct Node* headNode)
{
	FILE* fp = fopen(fileName, "r");
	if (fp == NULL)
	{
		//不存在就创建出来这个文件
		fp = fopen(fileName, "w+");
	}
	struct bookInfo tempData;
	while (fscanf(fp, "%s\t%f\t%d\n", tempData.name, &tempData.price, &tempData.num) != EOF)
	{
		insertNodeByHead(list, tempData);
	}
	fclose(fp);
}
//冒泡排序（链表）
void bubbleSortList(struct Node* headNode)
{
	for (struct Node* p = headNode->next; p != NULL; p = p->next)
	{
		for (struct Node* q = headNode->next; q->next != NULL; q = q->next)
		{
			if (q->data.price > q->next->data.price)
			{
				//交换值
				struct bookInfo tempData = q->data;
				q->data = q->next->data;
				q->next->data = tempData;
			}
		}
	}
	printList(headNode);
}


//2.交互
void keyDown()
{
	int userkey = 0;
	struct bookInfo tempBook;  //产生一个临时的变量存储书籍信息
	struct Node* result = NULL;
	scanf("%d", &userkey);
	switch (userkey) {
	case 0:
		printf(" 【 登记 】 \n");
		printf("输入书籍的信息(name,price,num):");
		scanf("%s%f%d", tempBook.name, &tempBook.price, &tempBook.num);
		insertNodeByHead(list, tempBook);
		saveInfoToFile("bookinfo.txt", list);
		break;
	case 1:
		printf(" 【 浏览 】 \n");
		printList(list);
		break;
	case 2:
		printf(" 【 借阅 】 \n"); 
		printf("请输入你要借阅的书籍：");
		scanf("%s", tempBook.name);
		result = searchByName(list,tempBook.name);
		if (result == NULL)
			printf("没有相关书籍无法借阅！\n");
		else
		{
			if (result->data.num > 0)
			{
				result->data.num--;
				printf("借阅成功\n");
				saveInfoToFile("bookinfo.txt", list);
			}
			else
			{
				printf("当前书籍无库存，借阅失败！\n");
			}
		}
		break;
	case 3:
		printf(" 【 归还 】 \n");
		printf("请输入你要归还的书籍：");
		scanf("%s", tempBook.name);
		result = searchByName(list, tempBook.name);
		if (result == NULL)
			printf("书籍来源非法！\n");
		else
		{
			result->data.num++;
			printf("书籍归还成功！\n");
			saveInfoToFile("bookinfo.txt", list);
		}
		break;
	case 4:
		printf(" 【 查找 】 \n");
		printf("你要查询的书名：");
		scanf("%s", tempBook.name);
		result = searchByName(list, tempBook.name);
		if (result == NULL)
		{
			printf("未找到相关结果!\n");
		}
		else
		{
			printf("书名\t价格\t数量\n");
			printf("%s\t%.1f\t%d\n", result->data.name, result->data.price, result->data.num);
		}
		break;
	case 5:
		printf(" 【 排序 】 \n");
		bubbleSortList(list);
		break;
	case 6:
		printf(" 【 删除 】 \n");
		printf("输入想要删除的书名:");
		scanf("%s", tempBook.name);
		deleteNodeByName(list, tempBook.name);
		saveInfoToFile("bookinfo.txt", list);
		break;
	case 7:
		printf(" 【 退出 】 \n");
		printf(" 退出成功 \n");
		system("pause");
		exit(0);   //关掉整个程序
		break;
	default:
		printf(" 【 error 】 \n");
		break;
	}
}

//1.界面--->菜单--->模块
void makeMenu()
{
	printf("----------------------------------\n");
	printf("  Eugeo图书管理借阅系统\n");
	printf("t0.登记书籍\n");
	printf("t1.浏览书籍\n");
	printf("t2.借阅书籍\n");
	printf("t3.归还书籍\n");
	printf("t4.查找书籍\n");
	printf("t5.排序书籍\n");
	printf("t6.删除书籍\n");
	printf("t7.退出系统\n");
	printf("----------------------------------\n");
	printf("请输入(0~7):");
}

int main()
{
	list = createHead();  //链表初始化
	readInfoFromFile("bookinfo.txt", list);
	while (1)
	{
		makeMenu();
		keyDown();
		system("pause");
		system("cls");
	}

}