我试图在我的程序中使用队列，但它无法编译，我不知道为什么。代码的相关部分如下。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>

#ifndef CUSTOMER
#define CUSTOMER

typedef int bool;

int r;

typedef struct{

    int arrival;
    int leaving;

} Customer;

static const int MAX_LENGTH = 100;

typedef struct{
    int head;
    int length;

    Customer customer[MAX_LENGTH];

} CustomerLine;

void initializeQueue(CustomerLine* queue)
{
    (*queue).head = 0;
    (*queue).length = 0;
}

bool hasNext(CustomerLine* queue)
{
    return (*queue).length > 0;
}

bool isFull(CustomerLine* queue)
{
    return (*queue).length == MAX_LENGTH;
}

bool enqueue(CustomerLine* queue, Customer* customer)
{

    if(isFull(queue))
        return 0;
    int index = ((*queue).head + (*queue).length) % MAX_LENGTH;
    (*queue).customer[index] = *customer;
    (*queue).length++;

    return 1;
}

Customer* dequeue(CustomerLine* queue)
{
    if(!hasNext(queue))
        return 0;

    Customer* result = &(*queue).customer[(*queue).head];

    (*queue).length--;
    (*queue).head = ((*queue).head + 1) % MAX_LENGTH;
    return result;
}

字符串
错误说：
在文件范围内可变修改的“客户”