Thread: incorrect output

I am just trying to write a program where a user enters a grade and then when -1 is entered the program outputs the average grade and exits. The code I have written compiles and works, but it subtracts 1 from the average. Confused as to why this is happening:

//grades
#include <iostream.h>

int main()
{
int count = 0;
int total = 0;
int average;
int grades = 0;
while(grades != -1)
{
cout << "Please enter a grade(enter -1 to quit): \n";
cin >> grades;
total += grades;
count++;}
count--;
average = total / count;
cout << "Class average is: " << average << endl;
return 0;
}

Try this instead of your while loop. If it corrects the problem I think you can figure out what went wrong in your solution. It is an important problem to be aware of as it can rear it's ugly head in many different scenarios.

cout << "Please enter a grade(enter -1 to quit): \n";
cin >> grades;
while(grades != -1)
{
total += grades;
count++;
cout << "Please enter a grade(enter -1 to quit): \n";
cin >> grades;
}

thanks for your help... it works fine now