c语言从文本中读出菜品信息，链表实现通过查询菜品类型点餐，修改订单，删除订单，计算总价

对于这个问题，需要设计一个菜品信息的数据结构，可以使用结构体来表示一个菜品的信息，包括菜品名称、菜品类型、价格等字段。然后使用链表来存储所有菜品的信息。

读取文本文件中的菜品信息，并将其存储到链表中，可以使用文件读取函数，逐行读取文件，并使用字符串处理函数来分离菜品信息中的各个字段。然后根据读取到的数据构建菜品信息结构体，并加入到链表中。

对于通过查询菜品类型点餐，可以实现一个函数，该函数接收一个菜品类型作为参数，然后遍历链表中的菜品信息，查找出所有符合条件的菜品，将它们显示出来，让用户选择需要点的菜品并输入数量。然后生成一个订单信息，存储订单的菜品名称、数量、单价等信息。

修改订单可以实现一个函数，该函数接收要修改的订单号和修改后的菜品信息，然后遍历订单列表，找到要修改的订单，将订单信息更新为新的菜品信息。

删除订单可以实现一个函数，该函数接收要删除的订单号，然后遍历订单列表，找到要删除的订单，将该订单从订单列表中删除。

计算总价可以实现一个函数，该函数遍历订单列表，累加所有订单的菜品数量和单价，计算出总价并返回给调用者。

整个程序的主要逻辑就是根据用户的输入来执行相应的操作，如查询菜品信息、点餐、修改订单、删除订单等等，每个操作都需要对菜品信息链表和订单列表进行相应的修改。在程序退出时，需要将所有菜品信息和订单信息存储到文件中。

相关问题

c语言从文本中读出菜品信息，链表实现通过查询点餐，修改订单，删除订单，计算总价

这里提供一个简单的代码示例，实现从文本文件中读取菜品信息，并使用链表实现点餐、修改订单、删除订单、计算总价等功能。

菜品信息包括名称、价格、数量，存储在一个文本文件dish.txt中，每行包括名称、价格、数量，用空格分隔。如下所示：

红烧肉 20 10
麻辣肥牛 30 5
鱼香肉丝 25 8
宫保鸡丁 22 12
...

代码实现如下：

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

#define MAX_LEN 50

// 菜品信息结构体
typedef struct dish_info
{
char name[MAX_LEN]; // 名称
float price; // 价格
int num; // 数量
struct dish_info* next; // 下一个节点指针
}DishInfo;

// 读取菜品信息
DishInfo* read_dish_info()
{
DishInfo* head = NULL;
DishInfo* tail = NULL;

FILE* fp = fopen("dish.txt", "r");
if(fp == NULL)
{
printf("Failed to open file\n");
exit(-1);
}

char buffer[MAX_LEN];
while(fgets(buffer, MAX_LEN, fp) != NULL)
{
// 解析每行的信息
char* name = strtok(buffer, " ");
float price = atof(strtok(NULL, " "));
int num = atoi(strtok(NULL, " "));

// 创建节点并加入链表中
DishInfo* temp = (DishInfo*)malloc(sizeof(DishInfo));
strcpy(temp->name, name);
temp->price = price;
temp->num = num;
temp->next = NULL;

if(head == NULL)
{
head = temp;
tail = temp;
}
else
{
tail->next = temp;
tail = temp;
}
}

fclose(fp);
return head;
}

// 打印菜单
void print_menu(DishInfo* head)
{
DishInfo* node = head;
printf("================= Menu =================\n");
while(node != NULL)
{
printf("%s\t%.2f\t%d\n", node->name, node->price, node->num);
node = node->next;
}
printf("=========================================\n");
}

// 查找菜品
DishInfo* find_dish(DishInfo* head, char* name)
{
DishInfo* node = head;
while(node != NULL)
{
if(strcmp(node->name, name) == 0)
{
return node;
}
node = node->next;
}
return NULL;
}

// 点餐
void order(DishInfo* head)
{
print_menu(head);

char name[MAX_LEN];
printf("Enter the dish name: ");
scanf("%s", name);

DishInfo* dish = find_dish(head, name);
if(dish == NULL)
{
printf("Dish not found!\n");
return;
}

int num = 0;
printf("Enter the quantity: ");
scanf("%d", &num);

if(num > dish->num)
{
printf("Not enough dishes, please choose another one or reduce the quantity!\n");
return;
}

dish->num -= num;
printf("Order success!\n");
}

// 修改订单
void modify_order(DishInfo* head)
{
char name[MAX_LEN];
printf("Enter the dish name to be modified: ");
scanf("%s", name);

DishInfo* dish = find_dish(head, name);
if(dish == NULL)
{
printf("Dish not found!\n");
return;
}

int num = 0;
printf("Enter the new quantity: ");
scanf("%d", &num);

if(num > dish->num)
{
printf("Not enough dishes, please choose another one or reduce the quantity!\n");
return;
}

dish->num -= num;
printf("Modify success!\n");
}

// 删除订单
void delete_order(DishInfo* head)
{
char name[MAX_LEN];
printf("Enter the dish name to be deleted: ");
scanf("%s", name);

DishInfo* node = head;
DishInfo* prev = NULL;

while(node != NULL)
{
if(strcmp(node->name, name) == 0)
{
if(prev == NULL)
{
head = node->next;
}
else
{
prev->next = node->next;
}
free(node);
printf("Delete success!\n");
return;
}
prev = node;
node = node->next;
}

printf("Dish not found!\n");
}

// 计算总价
void calculate_total_price(DishInfo* head)
{
float total_price = 0.0f;
DishInfo* node = head;
while(node != NULL)
{
total_price += node->price * node->num;
node = node->next;
}
printf("Total price: %.2f\n", total_price);
}

// 主函数
int main()
{
DishInfo* head = read_dish_info();

// 测试读取菜品信息
/*
DishInfo* node = head;
while(node != NULL)
{
printf("%s\t%.2f\t%d\n", node->name, node->price, node->num);
node = node->next;
}
*/

// 测试点餐
/*
order(head);
print_menu(head);
*/

// 测试修改订单
/*
modify_order(head);
print_menu(head);
*/

// 测试删除订单
/*
delete_order(head);
print_menu(head);
*/

// 测试计算总价
/*
calculate_total_price(head);
*/

int choice = 0;
while(1)
{
printf("=========== Ordering System ============\n");
printf("1. Print menu\n");
printf("2. Order\n");
printf("3. Modify order\n");
printf("4. Delete order\n");
printf("5. Calculate total price\n");
printf("6. Exit\n");
printf("=======================================\n");
printf("Enter your choice: ");
scanf("%d", &choice);

switch(choice)
{
case 1:
print_menu(head);
break;
case 2:
order(head);
break;
case 3:
modify_order(head);
break;
case 4:
delete_order(head);
break;
case 5:
calculate_total_price(head);
break;
case 6:
exit(0);
default:
printf("Invalid choice!\n");
break;
}
}

return 0;
}

C语言用链表实现顾客根据TXT文件中菜品信息完成对订单的增删改查，并输出txt文件

非常感谢您的提问！以下是C语言用链表实现顾客根据TXT文件中菜品信息完成对订单的增删改查，并输出txt文件的代码：

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

typedef struct dish {
    int id;
    char name[50];
    int price;
    struct dish *next;
} Dish;

Dish *head, *tail;

Dish *createDish(int id, char *name, int price) {
    Dish *dish = (Dish*)malloc(sizeof(Dish));
    dish->id = id;
    strcpy(dish->name, name);
    dish->price = price;
    dish->next = NULL;
    return dish;
}

void addDish(int id, char *name, int price) {
    Dish *dish = createDish(id, name, price);
    if (head == NULL) {
        head = dish;
    } else {
        tail->next = dish;
    }
    tail = dish;
}

void displayDishes() {
    Dish *dish = head;
    while (dish != NULL) {
        printf("%d\t%s\t%d\n", dish->id, dish->name, dish->price);
        dish = dish->next;
    }
}

void freeDishes() {
    Dish *dish = head;
    while (dish != NULL) {
        Dish *temp = dish->next;
        free(dish);
        dish = temp;
    }
    head = NULL;
    tail = NULL;
}

void readDishes(char *filename) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        printf("Failed to read file: %s\n", filename);
        return;
    }
    char line[100];
    while (fgets(line, sizeof(line), file)) {
        int id, price;
        char name[50];
        sscanf(line, "%d,%[^,],%d", &id, name, &price);
        addDish(id, name, price);
    }
    fclose(file);
}

void saveDishes(char *filename) {
    FILE *file = fopen(filename, "w");
    if (file == NULL) {
        printf("Failed to save file: %s\n", filename);
        return;
    }
    Dish *dish = head;
    while (dish != NULL) {
        fprintf(file, "%d,%s,%d\n", dish->id, dish->name, dish->price);
        dish = dish->next;
    }
    fclose(file);
}

void addOrder(int id, int quantity) {
    Dish *dish = head;
    while (dish != NULL) {
        if (dish->id == id) {
            dish->price *= quantity;
            return;
        }
        dish = dish->next;
    }
    printf("Dish not found with id: %d\n", id);
}

void removeOrder(int id) {
    Dish *dish = head;
    if (dish->id == id) {
        head = dish->next;
        free(dish);
        return;
    }
    while (dish->next != NULL) {
        if (dish->next->id == id) {
            Dish *toDelete = dish->next;
            dish->next = toDelete->next;
            free(toDelete);
            return;
        }
        dish = dish->next;
    }
    printf("Dish not found with id: %d\n", id);
}

void updateOrder(int id, int newPrice) {
    Dish *dish = head;
    while (dish != NULL) {
        if (dish->id == id) {
            dish->price = newPrice;
            return;
        }
        dish = dish->next;
    }
    printf("Dish not found with id: %d\n", id);
}

int main() {
    readDishes("dishes.txt");
    printf("Menu:\n");
    displayDishes();
    addOrder(1, 2);
    printf("Order updated:\n");
    displayDishes();
    removeOrder(2);
    printf("Order removed:\n");
    displayDishes();
    updateOrder(3, 50);
    printf("Order updated:\n");
    displayDishes();
    saveDishes("dishes_new.txt");
    freeDishes();
    return 0;
}

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