c - 餐厅模拟

Question

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#define Empty 1
#define Full 0

float ChanceOfArrival (float CustomersPerMinute)
{
float CustomersArrivalChance;
int i;

/*Customers arriving per second */

CustomersArrivalChance = (CustomersPerMinute / 60) * 100;

printf ("The chance of customers arriving is: %0.3f%%\n", CustomersArrivalChance);

/* each 10 minute interval */

for (i = 0; i <= 18; i++)
{
    intervals (CustomersArrivalChance);
}

return CustomersArrivalChance;
}

int intervals (CustomersArrivalChance)
{

int totalCustomers = 0, totalWait = 0, queue = 0, SecondsInterval, waitingCustomers = 0;
int Cash1Salad, Cash1Buger, Cash2Salad, Cash2Burger;
int Cash1 = 1, Cash2 = 1;
int cointoss;
int x, Empty1, Empty2;
int CustomersServed = 0;
float RatePerMinute = 0, AverageWait = 0;
static int intervalNumber;
srand(time(NULL));

/*What could possibly happen every second in a 10 minute interval */
for (SecondsInterval = 0; SecondsInterval <= 600; SecondsInterval++)
{
    x = rand() % 101;

    if (CustomersArrivalChance >= x)
    {
        /*Customers Arrive this second */

        totalCustomers++;
        queue++;
        /*Choosing a cash at random */

        cointoss = rand()%2;
     if (queue > 0)
     {



        /* Cash 1 is open cash 2 is busy so the customer goes to cash 1 and chooses
        at random what they want to eat */
        if ((Cash1 == Empty) && (Cash2 != Empty) || (cointoss == 1) )
        {
            Cash1 = Full;
            queue--;

            switch ((rand()%2))
            {
                case 0:
                    Cash1Salad = rand()% 66 + 55;
                    totalWait = totalWait + Cash1Salad;
                    Empty1 = Cash1Salad;
                    CustomersServed++;
                    break;
                case 1:
                    Cash1Buger = rand()% 130 + 111;
                    totalWait = totalWait + Cash1Buger;
                    Empty1 = Cash2Burger;
                    CustomersServed++;
                    break;
            }
        }

        /* Cash 1 is busy cash 2 is open customer goes to cash 2 and chooses what they want */
        else if (Cash2 = Empty)
        {
            Cash2 = Full;
            queue--;

            switch ((rand()%2))
            {
                case 0:
                    Cash2Salad = rand()% 75 + 65;
                    totalWait = totalWait + Cash2Salad;
                    Empty2 = Cash2Salad;
                    CustomersServed++;
                    break;
                case 1:
                    Cash2Burger = rand()% 140 + 121;
                    totalWait = totalWait + Cash2Burger;
                    Empty2 = Cash2Burger;
                    CustomersServed++;
                    break;
            }
        }

        /*Both cashes are busy so the customer has to wait until one cash opens */
        else
        {
            totalWait++;
            waitingCustomers++;

        }

        /*Clearing Cash 1 if someone went there */
        if (Empty1 > 0)
        {
            Empty1--;
        }
        /*empty1 is equal to 0 then cash 1 is empty */
        else
        {
            Cash1 = Empty;
        }
        /*Clearing cash 2 is someone went there */
        if (Empty2 > 0)
        {
            Empty2--;
        }
        /*empty2 is equal to 0 then cash 2 is empty */
        else
        {
            Cash2 = Empty;
        }
     }
    }
    else
    {
        /*nothing happens because no customer showed up */
    }

}

intervalNumber++;

AverageWait = ((totalWait*1.0)/ (totalCustomers));
printf ("The average waiting time per customer in seconds is %0.2f in the interval      %d\n\n", AverageWait, intervalNumber);

printf  ("The total customers that arrived in the interval %d is %d\n\n", intervalNumber, totalCustomers);

}


int main (void)
{
    float CustomersPerMinute;

    printf ("Enter in the number of customers you want to arrive per minute:\n");
    scanf ("%f", &CustomersPerMinute);

    ChanceOfArrival(CustomersPerMinute);


    return 0;
}

你好，我有这个程序，它假设模拟一家只供应沙拉或汉堡的餐厅，只有两个收银员，只有一个队列供顾客排队等候服务。

我不确定为什么它不起作用，但我相信一切都合乎逻辑，但是当我运行这个程序时，它只是打印出预期的平均等待时间。

但问题是打印的平均等待时间在每个时间间隔内都是相同的。这不是我想要的。

从逻辑上讲，我认为每个时间间隔的平均等待时间应该不同，因为客户是随机生成的。然而，情况并非如此，因为平均等待时间始终相同，我该如何解决这个问题？

此外，每个时间间隔的客户总数相同，但由于客户是随机生成的，所以应该不同，我该如何解决这个问题？

Answer 1

看起来你在循环 srand。因此，它可能会在给定的一秒内为您提供相同的 rand() 结果。 不过 Stack overflow 不是调试论坛 ;)。