#include <stdio.h>
#include <stdlib.h>
#include <string.h>

double calcAverage(int grades [], int numGrades);

void getData(char *fName, int grades[], int *numGrades);

int main (int argc, char *argv[]) {

   const int MAX_STUDENTS = 50;
   const int PASS_LEVEL = 70;
   
//   int grades[] = {42, 11, 100, 93, 70};
//   int numGrades = 5;

   int grades[MAX_STUDENTS];
   int numGrades = 0;
  
   getData("grades.txt", grades, &numGrades);

   printf("the number of students is %d\n", numGrades);

   for (int i = 0; i < numGrades; i++) {
      printf("%d - %d ", i, grades[i]);
   
      if (grades[i] >= PASS_LEVEL) {
         printf(", Passing\n");
      }
      else {
         printf(", Failing\n");
      }
   }

   double average = calcAverage(grades, numGrades);
   printf("The average = %f\n", average);

   return 0;
}

void getData(char *fName, int grades[], int *numGrades) {
 
   FILE *fptr;
   fptr = fopen(fName, "r");

   if (fptr == NULL) {
      printf("you screwed up\n");
      exit(-1);
   }
   else {
      int grade;
      char buf[BUFSIZ];
      
      while(fgets(buf,sizeof(buf), fptr)) {
printf("%s\n", buf);

         grade = atoi(buf);
         grades[*numGrades] = grade;

         (*numGrades)++; 
      }
   }
printf("in getData - numGrades = %d\n", *numGrades);

}

double calcAverage(int grades[], int numGrades) {
   double average;
   int total = 0;

   for (int i = 0; i < numGrades; i++) {
      total = total + grades[i];   //the same as total += grades[i];
   }

   average = total / (double) numGrades;

   return average;
}