static float * myVar initialization - c++

Question

Using C++, I declared the following static variable in a class SavingsAccount
static float *waitingInQueue;
But I'm not able to initialize the data pointed, I'm only able to initialize the address of the pointer as follows : float* SavingsAccount::waitingInQueue=0;
I would like the data of this pointer initialized at 0. I don't want to use a setter because I need to be able to initialized it once without using an object of the class SavingsAccount. I would like to do the following statement outside a function : *waitingInQueue=0;
Here is my header file :
#ifndef SAVINGSACCOUNT_H
#define SAVINGSACCOUNT_H
class SavingsAccount
{
public:
SavingsAccount();
float getInterestDue(){return *interestDue;};
float getAmountDue() {return *amountDue;};
int getArrivalTime() {return *arrivalTime;};
int getFinishTime() {return *finishTime;};
void setFinishTime(int newTime) {*finishTime=newTime;};
float computeInterestDue();
// compute the interest due...
float computeAmountDue();
// compute the total amount due
void waitingClient();
// increment *arrivalTime
void waitingProcess();
// increment *finishTime checking if there is not another client already processing, in that case make him wait during the previous client processing
void display();
// display the information about 1 client
void saveAccounts();
// save the information of the 20 clients
// void setWaitingInQueue(float x) {*waitingInQueue=x;}; <- can't be used
private:
float clientTable[8];
// information about a single client
static float globalTable[20][8];
static int clientCount;
float *customerID;
static float *arrivalTime;
static float *finishTime;
static const float depositType[6];
float *depositAmount;
static const float interestRate[12];
float *interestDue;
float *amountDue;
float *PtrDepType, *PtrRate;
static float *waitingInQueue;
};
#endif /* SAVINGSACCOUNT_H */
Here is my .cpp
#ifndef SAVINGSACCOUNT_CPP
#define SAVINGSACCOUNT_CPP
#include<cstdlib>
#include <iostream>
#include <ctime> // include to get the number of seconds since 1970 (srand))
#include <iomanip> // to set precision of numbers setprecision()
#ifdef WIN32
#include <windows.h> // for windows
#else
#include <unistd.h>
#endif // win32 // for unix
#include "SavingsAccount.h"
using namespace std;
float SavingsAccount::globalTable[20][8];
int SavingsAccount::clientCount=0;
const float SavingsAccount::depositType[6]={0.25, 0.5, 1, 2, 3, 5};
const float SavingsAccount::interestRate[]={1.71, 1.80, 2.07, 2.25, 2.25, 2.52, 2.70, 3.06, 3.24, 3.69, 3.60, 4.14};
float* SavingsAccount::arrivalTime;
float* SavingsAccount::finishTime;
float* SavingsAccount::waitingInQueue=0; // should be *waitingInQueue = 0;
SavingsAccount::SavingsAccount()
{
clientCount++;
int index;
srand(time(NULL)); //
index=rand()%6; //
customerID=&clientTable[0];
arrivalTime=&clientTable[1];
finishTime=&clientTable[2];
PtrDepType=&clientTable[3]; // &depositType[index]
depositAmount=&clientTable[4];
PtrRate=&clientTable[5]; // &interestRate[N]
interestDue=&clientTable[6];
amountDue=&clientTable[7];
*customerID=clientCount;
*PtrDepType=depositType[index];
*depositAmount=(rand()%49+1)*1000;
if (clientCount<=10) *PtrRate=interestRate[2*index]; // N=2*index
else *PtrRate=interestRate[2*index+1]; // N=2*index+1
}
float SavingsAccount::computeInterestDue()
{
*interestDue=*PtrDepType*(*depositAmount)**PtrRate*(1-0.2)/100;
}
float SavingsAccount::computeAmountDue()
{
*amountDue=*depositAmount+*interestDue;
}
void SavingsAccount::waitingClient()
{
if (clientCount==1) *arrivalTime=0;
else {
int milliseconds=(rand()%6+3)*1000; // random time in milliseconds
#ifdef WIN32 // for windows
Sleep(milliseconds);
#else // for unix
usleep(milliseconds * 1000); // nano seconds have to be multiplied by 1000
#endif // win32
*arrivalTime = *arrivalTime+milliseconds/1000;
}
}
void SavingsAccount::waitingProcess()
{
if(*finishTime < *arrivalTime)
{
*waitingInQueue =*arrivalTime-*finishTime;
}
int milliseconds=(rand()%6+2)*1000; // random time in milliseconds
#ifdef WIN32
Sleep(milliseconds);
#else
usleep(milliseconds * 1000);
#endif // win32
*finishTime= *arrivalTime + milliseconds/1000 + *waitingInQueue;
}
void SavingsAccount::saveAccounts()
{
globalTable[clientCount-1][0]=*customerID;
globalTable[clientCount-1][1]=*arrivalTime;
globalTable[clientCount-1][2]=*finishTime;
globalTable[clientCount-1][3]=*PtrDepType;
globalTable[clientCount-1][4]=*depositAmount;
globalTable[clientCount-1][5]=*PtrRate;
globalTable[clientCount-1][6]=*interestDue;
globalTable[clientCount-1][7]=*amountDue;
}
void SavingsAccount::display()
{
cout << setprecision(0) << setw(4) << right << clientTable[0];
cout << setprecision(0) << setw(7) << right << clientTable[1];
cout << setprecision(0) << setw(8) << right << clientTable[2];
cout << setprecision(2) << setw(10) << right << fixed << clientTable[3];
cout << setprecision(2) << setw(12) << right << clientTable[4];
cout << setprecision(2) << setw(7)<< right << clientTable[5];
cout << setprecision(2) << setw(12)<< right << clientTable[6];
cout << setprecision(2) << setw(12)<< right << clientTable[7] << endl;
}
#endif
The idea of the program is to display information about 20 clients that are arriving every x seconds (3static float *waitingInQueue; to increase the finishing time of all the client if needed.
If you have any other idea to easily simulated a queue I would be interested.

Answer 1

Even if *waitingInQueue = 0; were valid outside a function, it would be incorrect because you're initializing the pointer to null.
The easiest way to do what you're asking is something like this:
class SavingsAccount
{
...
private:
static float zero;
static float* waitingInQueue;
};
float SavingsAccount::zero = 0.0f;
float SavingsAccount::waitingInQueue = &SavingsAccount::zero;

Answer 2

You can initialise your static variable in many different ways -- but you should be asking a different question - "How can I get rid of my static variables?". static variables are often a sign that something is not quite right, and in that light I think you have a pretty large design problem here.
I'd group all your static variables into a Branch object. Then have each SavingsAccount have a pointer to their Branch. And add a newAccount() to Branch for creation. Then you have no more statics and everything is neater (and easier to test).
There also seems to be a lot of uses of pointers where non-pointer types would be OK, and cases where fixed length arrays are used, but would be improved by switching to std::vector<>