Mam problem z zakończeniem pętli cin w moim programie. Mój program używa przekierowania Linuksa do odczytu danych wejściowych z pliku hw07data, plik danych wygląda tak:

100 20 50 100 40 -1 
A34F 90 15 50 99 32 -1
N12O 80 15 34 90 22 -1

Pierwsza część to suma punktów dla klasy, następne wiersze to numer identyfikacyjny ucznia, a po nim ich wyniki, wszystkie zakończone o -1.

Mój problem: moja pętla while nigdy nie kończy się po uruchomieniu polecenia./a.out <hw07data, czy ktoś może przejrzeć mój kod i dać mi kilka wskazówek? Nie chcę odpowiedzi, ponieważ to zadanie domowe, potrzebuję tylko wskazówek. Dzięki!!

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

const int SENTINEL = -1;           //signal to end part of file
const int LTAB = 8;                //left tab
const int RTAB = 13;               //right tab

int main()
{
    cout << "Grant Mercer Assignment 7 Section 1002\n\n";
    cout << setprecision(2) << fixed << showpoint;
    cout << left << setw(LTAB) << "ID CODE" <<
                right << setw(RTAB) << "POINTS" <<
                setw(RTAB) << "PCT" << setw(RTAB) <<
                 "GRADE" << endl;
    double Percentage,              //holds students percentage
           AvgPercentage;
    int Earnedpoints,               //earned points for specific student
        Totalpoints,                //total points possible for all students
        AvgPoints,                  //average points for all students
        NumClass;                   //counts the number of students
    Totalpoints = Earnedpoints =    //set all vals equal to zero
    AvgPoints = AvgPercentage = Percentage =  NumClass = 0;
                                    //first and last char for studentID
    char Fchar,Lchar, Num1, Num2, Grade;

    int TmpVal = 0;                 //temporary value
    cin >> TmpVal;
    while(TmpVal != -1)             //reading in TOTAL POINTS
    {
        Totalpoints += TmpVal;      //add scores onto each other
        cin >> TmpVal;              //read in next value
    }

    while(cin)                       //WHILE LOOP ISSUE HERE!
    {
                                     //read in student initials
            cin >> Fchar >> Num1 >> Num2 >> Lchar >> TmpVal;
            while(TmpVal != -1)
            {
                Earnedpoints += TmpVal; //read in points earned
                cin >> TmpVal;
            }
                                        //calculate percentage
            Percentage = ((double)Earnedpoints / Totalpoints) * 100;
            AvgPercentage += Percentage;
            NumClass++;
            if(Percentage >= 90)        //determine grade for student
                Grade = 'A';
            else if(Percentage >= 80 && Percentage < 90)
                Grade = 'B';
            else if(Percentage >= 70 && Percentage < 80)
                Grade = 'C';
            else if(Percentage >= 60 && Percentage < 70)
                Grade = 'D';
            else if(Percentage < 60)
                Grade = 'F';
                                        //display information on student


            cout << left << Fchar << Num1 << Num2 << setw(LTAB) << Lchar << right << setw(RTAB-3) << Earnedpoints <<
            setw(RTAB) << Percentage <<  setw(RTAB) << Grade << endl;
            TmpVal = Earnedpoints = 0;
    }
    AvgPercentage /= NumClass;
    cout << endl << left << setw(LTAB+20) << "Class size: " << right << setw(RTAB) << NumClass << endl;
    cout << left << setw(LTAB+20) << "Total points possible: " << right << setw(RTAB) << Totalpoints << endl;
    cout << left << setw(LTAB+20) << "Average point total: " << right << setw(RTAB) << AvgPoints << endl;
    cout << left << setw(LTAB+20) << "Average percentage: " << right << setw(RTAB) << AvgPercentage << endl;
}

Wyjście nadal pyta o nowe wejście.