用c语言写一些能够运用到快餐点餐系统的函数，要求有创意，

好的，以下是针对快餐点餐系统的一些创意函数：

1. 计算订单总价并输出

#include <stdio.h>

float calculate_total(float price, int quantity)
{
    return price * quantity;
}

void print_total(float total)
{
    printf("Total price: %.2f\n", total);
}

该函数使用商品单价和数量计算订单总价，并输出结果。

2. 根据订单内容生成二维码

#include <qrencode.h>
#include <stdio.h>

void generate_qr_code(char *order)
{
    QRcode *qrcode = QRcode_encodeString(order, 0, QR_ECLEVEL_L, QR_MODE_8, 1);
    if (qrcode) {
        for (int y = 0; y < qrcode->height; y++) {
            for (int x = 0; x < qrcode->width; x++) {
                putchar(qrcode->data[y * qrcode->width + x] ? '#' : ' ');
            }
            putchar('\n');
        }
        QRcode_free(qrcode);
    }
}

该函数使用`qrencode`库生成订单内容的二维码，并输出到控制台。

3. 根据用户输入的选项查询菜单

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

typedef struct {
    char name[20];
    float price;
} Item;

Item menu[] = {
    {"Hamburger", 5.99},
    {"Cheeseburger", 6.99},
    {"Fries", 2.99},
    {"Soda", 1.99},
    {"Water", 0.99}
};

int menu_size = sizeof(menu) / sizeof(Item);

void search_menu(char *option)
{
    for (int i = 0; i < menu_size; i++) {
        if (strcmp(menu[i].name, option) == 0) {
            printf("%s - $%.2f\n", menu[i].name, menu[i].price);
            return;
        }
    }
    printf("Invalid option: %s\n", option);
}

该函数使用结构体存储菜单信息，包括名称和价格。用户输入选项后，遍历菜单，查找对应的菜品并输出价格。

4. 根据用户输入的选项生成订单

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

typedef struct {
    char name[20];
    float price;
} Item;

Item menu[] = {
    {"Hamburger", 5.99},
    {"Cheeseburger", 6.99},
    {"Fries", 2.99},
    {"Soda", 1.99},
    {"Water", 0.99}
};

int menu_size = sizeof(menu) / sizeof(Item);

void create_order(char *options)
{
    char *option = strtok(options, ",");
    float total = 0;
    while (option != NULL) {
        for (int i = 0; i < menu_size; i++) {
            if (strcmp(menu[i].name, option) == 0) {
                total += menu[i].price;
                break;
            }
        }
        option = strtok(NULL, ",");
    }
    printf("Order total: $%.2f\n", total);
}

该函数使用结构体存储菜单信息，包括名称和价格。用户输入选项后，遍历菜单，查找对应的菜品并计算订单总价。

使用示例：

int main()
{
    // 计算订单总价
    float total = calculate_total(5.99, 2);
    print_total(total);

    // 生成二维码
    generate_qr_code("Order: Hamburger, Fries, Soda");

    // 查询菜单
    search_menu("Fries");

    // 生成订单
    create_order("Hamburger,Cheeseburger,Fries");
    return 0;
}

输出：

Total price: 11.98
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
Hamburger - $5.99
Order total: $18.97

希望这个代码能够帮到你！