Cin loop never terminating - c++

Question

I'm having trouble getting my cin loop to terminate in my program. My program uses Linux redirection to read in input from the file hw07data, the data file look like this:
100 20 50 100 40 -1
A34F 90 15 50 99 32 -1
N12O 80 15 34 90 22 -1
The first portion is the total points for the class, the next lines are the students ID number followed by their scores, all terminated by -1.
My issue: my while loop never terminates when i run the command ./a.out < hw07data, could anyone look over my code and give me some hints? I dont want the answer, as this is homework, i just need some guidance. Thanks!!
#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;
}
The output continues to ask for new input.

Answer 1

You may find answer there How to read until EOF from cin in C++
So you can read cin line by line using getline and parse the resulting lines, like that:
#include <iostream>
#include <sstream>
#include <string>
int main() {
int a, b;
std::string line;
while (std::getline(std::cin, line)) {
std::stringstream stream(line);
stream >> a >> b;
std::cout << "a: " << a << " - b: " << b << std::endl;
}
return 0;
}
EDIT: Do not forget to check parsing results and stream state for any failure!

Answer 2

You should always check that you input was successful:
if (std::cin >> TmpVal) {
// do simething with the read value
}
else {
// deal with failed input
}
In case of a failure you night want to check eof() inducating that the failure was due to having reached the end of the input.
To deal with errors, have a look at std::istream::clear() and std::istream::ignore().