trying to add a sum function in a class program - help

I am just starting to program and have an assignment where we need to use classes for an employee payroll program. Everything is working fine until I try to add a function that calculates the sum of netpays. I think that I need to enter a loop in the findsumnetpay funtion but have not had any luck. Please help to guide me in the right direction.
Here is the code:

Code:

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#include <fstream>
#include <iostream>
#include <string>
#include <iomanip>
 
 using namespace std;
//file input output stream
 
 
//function prototypes
class payroll{
public:  ifstream fin;
        char employeeid[6];
      char employeename[12];
      int hoursworked, overtime;
      double hourlyrate,overtimepay,regularpay,grosspay,taxrate,taxamount,netpay,sumnetpay;
      void calculategrosspay();
      void calculatetax();
      void calculatenetpay();
      double findsumnetpay();
      void printheadings();
      void printdata();
     
public:payroll();
~payroll();
void printreport(); };
payroll::payroll(){
                  fin.open("employee8.in");}
payroll::~payroll(){
                  fin.close(); }//DESTRUCTOR
                 
void payroll::calculategrosspay(){
    if(hoursworked>40){
    overtime = hoursworked-40;
    regularpay = hoursworked * hourlyrate;
    overtimepay = overtime *(hourlyrate *1.5);
    grosspay = regularpay + overtimepay; }
else grosspay = hoursworked * hourlyrate;  }//CALCULATGROSSPAY
   
void payroll::calculatetax(){
    taxamount = grosspay * .30;  }//CALCULATETAX

void payroll::calculatenetpay(){
    netpay = grosspay - taxamount;
    }//CALCULATENETPAY
   
double payroll::findsumnetpay(){
    sumnetpay = sumnetpay+netpay;
    return sumnetpay;}//FINDSUMNETPAY   
 
void payroll::printheadings(){
    cout<<setw(45)<<"-PAYROLL REPORT-"<<endl;
    cout<<"-------------------------------------------------------------------------"<<endl;
    cout<<"NAME      ID        HW    RT-PAY    OT-PAY    GROSS"
    "    TAX      NETPAY"<<endl;
    cout<<"-------------------------------------------------------------------------"<<endl;
    }//PRINTHEADINGS
   
void payroll::printdata(){
    cout<<setprecision(2)<<setiosflags(ios::fixed|ios::showpoint);
    cout<<setw(8)<<employeename<<setw(6)<<employeeid<<setw(8)<<hoursworked<<
    setw(11)<<regularpay<<setw(11)<<overtimepay
    <<setw(10)<<grosspay<<setw(10)<<taxamount<<setw(10)
    <<netpay<<endl;}

void payroll::printreport(){
    int i;
    printheadings();
    while(fin>>employeename>>employeeid>>hoursworked>>hourlyrate){
        calculategrosspay();
        calculatetax();
        calculatenetpay();
        findsumnetpay();
        printdata();

        i++;  }//WHILE       
   
    //FINDSUMNETPAY
       
        }//PRINTREPORT
       
int main(){
    payroll employee;
    employee.printreport();
    cout<<employee.sumnetpay<<endl;
    system("Pause");
    }//MAIN

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Dear friend,

Your code looks excellent thus far, have you yet studied iostreams? Perhaps this would be a good time to use cin.

So sumnetpay starts out as "random". You then add something to it, which makes it "random". You then print it out, which means you get "random". Maybe you should start sumnetpay to have some initial value.

I am going to give you readability advice.
First, don't put the "}" on the ending row; put it on the NEXT row. It helps readability considerably.
Secondly, you MUST indent better. Refer to http://cpwiki.sourceforge.net/Indentation if you don't know how.
Thirdly, try putting spaces here and there in your code. For example:

Code:

---

void payroll::printdata(){
    cout<<setprecision(2)<<setiosflags(ios::fixed|ios::showpoint);
    cout<<setw(8)<<employeename<<setw(6)<<employeeid<<setw(8)<<hoursworked<<
    setw(11)<<regularpay<<setw(11)<<overtimepay
    <<setw(10)<<grosspay<<setw(10)<<taxamount<<setw(10)
    <<netpay<<endl;}

---

Readable code:

Code:

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void payroll::printdata()
{
    cout << setprecision(2) << setiosflags(ios::fixed | ios::showpoint);
    cout << setw(8) << employeename << setw(6) << employeeid << setw(8) << hoursworked
          << setw(11) << regularpay << setw(11) << overtimepay
          << setw(10) << grosspay << setw(10) << taxamount << setw(10)
          << netpay << endl;
}

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And lastly, try indenting some more if you break one line into several so you can easily identify that those additional lines belong to the line above.
See how much easier it became to read the code?