Need help with the void Dequeue function (last function)

[bluemoon3701]

In this program, you will implement a FIFO or FCFS Queue.

The data:
1) Define a structure named Customer with four members:
CustomerName: 15-character string, which is the name of the customer
ArrivalTime: integer, which is the arrival time of the customer
ServiceTime: integer, which is the time point that the customer starts to be serviced
FinishTime: integer, which is the leaving time of the customer

2) Define a structure named FCFSQueue with two members:
CustomerList: an array of 100 elements of type Customer;
length: integer, which is the number of the customers in the queue.

This program has four functions:
1. function IsEmpty check whether the queue is empty or not. Return true if empty, otherwise return false;
2. function GetLength will returns the number of customers in the queue;
3. function Enqueue will insert a new customer to the tail of the queue;
4. function Dequeue will remove a customer from the head of the queue.

Your main program will test these functions.

#include<iostream>
#include<string>

using namespace std;

struct Customer{
	string CustomerName;
	int ArrivalTime;
	int ServiceTime;
	int FinishTime;
};

struct FCFSQueue{
	Customer CustomerList[100];
	int length;
};

bool IsEmpty(FCFSQueue);
int GetLength(FCFSQueue);
void Enqueue(FCFSQueue&, Customer);
void Dequeue(FCFSQueue&, Customer&);

int main()
{
	FCFSQueue myQueue;
	myQueue.length = 0;
	Customer newCus;
	newCus.CustomerName = "Tom";
	newCus.ArrivalTime = 1;
	newCus.ServiceTime = 0;
	newCus.FinishTime = 0;
	Enqueue(myQueue, newCus);
	newCus.CustomerName = "Bob";
	newCus.ArrivalTime = 3;
	newCus.ServiceTime = 0;
	newCus.FinishTime = 0;
	Enqueue(myQueue, newCus);

	for (int i = 0; i < myQueue.length; i++)
	{
		cout << myQueue.CustomerList[i] << endl;
	}
	
	Dequeue(myQueue, newCus);
	Dequeue(myQueue, newCus);
	Dequeue(myQueue, newCus);
}
bool IsEmpty(FCFSQueue queue)
{
	if (queue.length == 0)
		return true;
	return false;
}
int GetLength(FCFSQueue queue)
{
	return queue.length;
}
void Enqueue(FCFSQueue &queue, Customer cus)
{
	if (queue.length < 100)
	{
		queue.CustomerList[queue.length] = cus;
		++queue.length;
	}
	else
	{
		cout << "The queue is full" << endl;
	}
}
void Dequeue(FCFSQueue &queue, Customer &cus)
{
	if (queue.length != 0)
	{
		queue.CustomerList[queue.length] = cus;
		--queue.length;
	}
	else
	{
		cout << "The queue is empty" << endl;
	}
}