bank.cpp

// bank.cpp -- using the Queue interface
// compile with queue.cpp
#include <iostream>
#include <cstdlib> // for rand() and srand()
#include <ctime> // time()
#include "queue.h"
const int MIN_PER_HR = 60;
bool newcustomer(double x); // is there a new customer?

int main()
{

    using std::cin;
    using std::cout;
    using std::endl;
    using std::ios_base;
    // setting things up
    std::srand(std::time(0));// random initializing of rand()
    cout << "Case Study: Bank of Heather Automatic Teller\n";
    cout << "Enter maximum size of queue: ";
    int qs;
    cin >> qs;
    Queue line(qs); // line queue holds up to qs people

    cout << "Enter the number of simulation hours: ";
    int hours;
    cin >> hours;
    // simulation will run 1 cycle per minute
    long cyclelimit = MIN_PER_HR * hours; // # of cycles
    cout << "Enter the average number of customers per hour: ";
    double perhour;
    cin >> perhour;
    double min_per_cust;// average time between arrivals
    min_per_cust = MIN_PER_HR / perhour;

    Item temp; // new customer data;
    long turnaways = 0; // turned away by full queue
    long customers = 0; // joined the queue
    long served = 0; // served during the simulation
    long sum_line = 0; // cumulative line length
    int wait_time = 0;// time until autoteller is free
    long line_wait = 0; // cumulative time in line
    // running the simulation
    for(int cycle =0 ;cycle < cyclelimit;cycle++)
    {
        if(newcustomer(min_per_cust)) // have newcomer;
        {
            if(line.isfull())
                turnaways++;
            else
            {
                customers++;
                temp.set(cycle); // cycle = time of arrival
                line.enqueue(temp); // add newcomer to line

            }
        }

        if(wait_time <=0 && !line.isempty())
        {
            line.dequeue(temp); // attend nextcustomer
            wait_time = temp.ptime(); // for wait_time minutes
            line_wait += cycle - temp.when();
            served++;
        }
        if(wait_time > 0)
            wait_time--;
        sum_line += line.queueCount();
    }


    // reporting results
    if(customers > 0)
    {
        cout << "customers accepted: " << customers << endl;
        cout << "  customers served: " << served << endl;
        cout << "         turnaways: " << turnaways << endl;
        cout << "average queue size: ";
        cout.precision(2);
        cout.setf(ios_base::fixed,ios_base::floatfield);
        cout << (double) sum_line / cyclelimit << endl;
        cout << " average wait time: "
             << (double) line_wait / served << " minutes \n";
    }
    else
    {
        cout << "No customers!\n";
    }

    cout << "Done !\n";
    return 0;


}


// x = average time, in minutes ,between customers
// return value is true if customer shows up this minute
bool newcustomer(double x)
{
    return (std::rand() * x / RAND_MAX < 1);
}