C++ program on single server queuing

Question

I am trying to make a program for my 'operation research' class. I have written code that works like a flowchart for a single server queuing system.

I am getting multiple errors (which seem simple), but I can’t figure out how to fix them. Some examples are 'missing terminating character', 'stray', and 'not declared in this scope'. How can I fix them?

#include <iostream>
#include <cmath>
using namespace std;

const int BUSY = 1;
const int IDLE = 0;

int
    choice,
    WL,
    SS;

double
    MX,
    IT,
    ST,
    TM,
    AT,
    DT,
    TypeOfEvent,
    NextServiceTime,
    ProgressAT’
    ProgressDT;


void  initialize();
void  Timing();
void  Arrival();
void  Departure();
float expon(float mean);

int main()
{
    initialize();
    do
    {
        cout<<"Enter your Policy: ";
        cin>>choice;
    }
    while(choice>2 || choice<1);

    cout << "'End of Simulation’ Time: " << MX << endll;

    while(true)
    {
        Timing();   // To determine the next event

        if(TM > MX)
            break;

        switch (int(TypeOfEvent))
        {
            case 1:
                Arrival();
                break;

            case 2:
                Departure();
                break;
        }
    }
    return 0;
}

void initialize()
{
    IT = 1.0;
    ST = 0.5;
    TM = 0.0;
    SS = IDLE;
    WL = 0;
    AT = TM + expon(IT);          // Arriving
    NextServiceTime = expon(ST);
    DT = 1.0e+10;                 // Guaranteeing that the first 
                                  // event is arriving
    ProgressAT = 0.0;
    ProgressDT = 0.0;
}

void Timing()
{
    TypeOfEvent = 0;

    if(AT < DT)
    {
        TypeOfEvent = 1;
        TM = AT;
    }
    else
    {
        TypeOfEvent = 2;
        TM = DT;
    }

    if (TypeOfEvent == 0)
    {
        cout << "System Idle " << TM;
        exit(1);
    }
}

void Arrival()
{
    if (SS == BUSY)
    {
        ++WL;
        ServiceTime[WL] = NextServiceTime;
    }
    else
    {
        SS = IDLE;
        DT = TM + NextServiceTime;
    }

    AT = TM + expon(IT);
    NextServiceTime = expon(ST);
}

void Departure()
{
    if (WL == 0)
    {
        SS = IDLE;
        DT = 9999;
    }
    else
    {
        if(choice == 2)
        {
            DT = TM + NextServiceTime;
        }
        --WL;
    }
}