#include <iostream>
using namespace std;

void computeMaxAndMin(double data[], int size, double & max, double & min);
void computeAverage(double data[], int size, double & average);

void computeMaxAndMin(double data[], int size, double & max, double & min)
{
     int index;

     max = data[0];
     min = data[0];
     for (index = 1; index < size; index = index + 1)
     {
          if (data[index] > max) max = data[index];
          else if (data[index] < min) min = data[index];
     }
}
void computeAverage(double data[], int size, double & average)
{
     int index;
     double sum;

     for (index = 0; index < size; index = index + 1)
     {
          sum = sum + data[index];
     }
     average = sum / size;
}

int main(int argc, char* argv[])
{
     const int CAPACITY = 1000;
     
     double testGrades[CAPACITY];
     int size;
     int index;
     double grade;
     double testMaxScore, testMinScore;
     double testAverageScore;

     cout << "Test Grade Analysis Program" << endl;
     cout << "Please enter the test grades, separated by spaces (maximum of " << CAPACITY << " can be entered). " << endl;
     cout << "Enter a value less than 0 to quit" << endl;

     // a value less than 0 is a SENTINEL (tells you when to quit, is not a legal value for grades)
     size  = 0;
     cin >> grade;

     while ((grade > 0) && (size < CAPACITY))
     {
          testGrades[size] = grade;
          size = size + 1;

          // you may have just filled up the array; if so, get out; if not, read the next grade
          if (size < CAPACITY) cin >> grade;
     }

     // at this point, the grade last entered was < 0 and was not written into the array
     // every time anything was actually written into the array, the size was incremented, so size is correct

     // pass size, not CAPACITY, to array functions
     // a size of 0 is possible, so handle those (averages, min, max undefined in such as case)
     if (size > 0)
     {
          computeMaxAndMin(testGrades, size, testMaxScore, testMinScore);
          cout  << "Max grade was " << testMaxScore << " and min grade was " << testMinScore << endl;
          computeAverage(testGrades, size, testAverageScore);
          cout << "Average was: " << testAverageScore << endl;
     }
     else cout << "No scores were entered, so no max, min, or average score could be computed." << endl;
}