程序代码：

#include <stdio.h>

#define TAX 0.05

char *foodMenu[]= {"fish","chips","hamburgers","with cheese"};
float foodPrice[]= {3.00,2.00,3.00,4.00};
int foodOrder[]= {0,0,0,0};

char *drinkMenu[]= {"soft drinks","coffees or teas"};
float drinkPrice[]= {1.00,1.00};
int drinkOrder[]= {0,0};

int OrderFood(char ** foodMenu,int foodOrder[]);
float ComputeFood(int foodOrder[]);

int OrderDrink(char ** drinkMenu,int drinkOrder[]);
float ComputeDrink(int drinkOrder[]);

int main(void)
{
    do {
        system("cls");
        printf("CFOOD FISH && CHIPS && BURGERS\n\n");
        OrderFood(foodMenu,foodOrder);
        OrderDrink(drinkMenu,drinkOrder);

        float priceFood=ComputeFood(foodOrder);
        float priceDrink=ComputeDrink(drinkOrder);
        float priceTotal=priceFood+priceDrink;
        float tax=TAX*priceTotal;
        float owing=priceTotal*(1.0+TAX);

        printf("Total Food\t%5.2f\n",priceFood);
        printf("Total Drink\t%5.2f\n",priceDrink);
        putchar('\n');
        printf("Total Order\t%5.2f\n",priceTotal);
        printf("Tax\t\t%5.2f\n",tax);
        printf("----------------------------\n");
        printf("Total owing\t%5.2f\n",owing);

        float money=0.0;
        float moneyGet;
PAY:
        printf("\nPlease give me the money:");
        while(scanf("%f",&moneyGet)!=1)
            fflush(stdin);
        money+=moneyGet;
        if(money<owing)
            goto PAY;

        printf("Amount tendered\t%.2f\n\n",money);

        float change=money-owing;
        printf("Chang\t\t%5.2f\n",change);

        fflush(stdin);
    } while(getchar()!='N');

    return 0;
}

int OrderFood(char ** foodMenu,int foodOrder[])
{
    printf("--------FOOD\n");
    int i;
    for(i=0; i<sizeof(foodMenu); i++)
    {
        printf("How many orders of %s?\tprice:$%.2f\n",foodMenu[i],foodPrice[i]);
        while(scanf("%d",&foodOrder[i])!=1)
            fflush(stdin);
    }
    putchar('\n');
    return 0;
}

int OrderDrink(char ** drinkMenu,int drinkOrder[])
{
    printf("--------DRINK\n");
    int i;
    for(i=0; i<sizeof(drinkMenu)-2; i++)//这里不减2就会出现越界读取的问题，不知道为什么，在OrderFood函数里也有类似一句，但它工作正常，我猜应该会有隐含的问题，望高手解答，谢谢
    {
        printf("How many %s?\tprice:$%.2f\n",drinkMenu[i],drinkPrice[i]);
        while(scanf("%d",&drinkOrder[i])!=1)
            fflush(stdin);
    }
    putchar('\n');
    return 0;
}

float ComputeFood(int foodOrder[])
{
    float total=0.00;
    int i;
    for(i=0; i<sizeof(foodPrice)/sizeof(float); i++)
    {
        total+=(foodOrder[i]*foodPrice[i]);
        if(i==3)
        {
            total-=(foodOrder[3]*foodPrice[2]);
            total+=(foodOrder[3]*foodPrice[5]);
        }
    }
    return total;
}

float ComputeDrink(int drinkOrder[])
{
    float total=0.00;
    int i;
    for(i=0; i<sizeof(drinkPrice)/sizeof(float); i++)
    {
        total+=(drinkOrder[i]*drinkPrice[i]);
    }
    return total;
}