C++ :: Displaying Average For Each Entry

I have to display an average for each student that is entered ....

void StudentData::displayAverageScore() {
double totalScore = 0;
double totalEx1 = 0, totalEx2 = 0, totalEx3 = 0, averageScore = 0;
for(int i = 0; i < entries.size(); i++) {
totalEx1 += entries[i].getEx1();// accumulate totals
totalEx2 += entries[i].getEx2();
totalEx3 += entries[i].getEx3();
if(totalScore != 0) averageScore = (totalEx1 + totalEx2 + totalEx3) / 3; // don't divide by 0
cout << "Average Score For Exams: " << setprecision(1) << fixed << averageScore << endl << endl;
}
}