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arrays and functions

badkaykay (96)
I am having trouble with the function I wrote, which is using values in an array. I am not sure what I did wrong, as this is my first time to write a function using array values/arrays.

Here is the code:
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#include <iostream>
#include <fstream>
#include <iomanip>
#include <math.h>

using namespace std;

float calcMean (float [], int);


int main()    
{

  const int size = 15;
  int arrSSN[size];
  float mean;
  float arrTest1[size];
  float arrTest2[size];
  float arrTest3[size];
  float arrProg1[size];
  float arrProg2[size];
  float arrProg3[size];
  float arrProg4[size];
  float arrProg5[size];
  float arrProg6[size];
  float arrFinal[size];
  float arrNumber[size];
  char arrLetter[size];

ifstream inc;
inc.open("studentScores.dat");
if (inc.fail() ) cout << "BAD" << endl;


int i = 0;
int countA = 0;
int countB = 0;
int countC = 0;
int countD = 0;
int countF = 0;

while (!inc.eof()) {
	
	inc >> arrSSN[i];
	inc >> arrTest1[i];
	inc >> arrTest2[i];
	inc >> arrTest3[i];
	inc >> arrProg1[i];
	inc >> arrProg2[i];
	inc >> arrProg3[i];
	inc >> arrProg4[i];
	inc >> arrProg5[i];
	inc >> arrProg6[i];
	inc >> arrFinal[i];


        //calculate individual overall score
        arrNumber[i] = ( (arrTest1[i] + arrTest2[i] + arrTest3[i]) * 50/300) + ( (arrProg1[i] + arrProg2[i] + arrProg3[i] + arrProg4[i] + arrProg5[i] + arrProg6[i]) * 25/300) + (arrFinal[i] * 25/100);

        if (arrNumber[i] >= 89.6) {
            arrLetter[i] = 'A';
	    countA++;

        }
        else if (arrNumber[i] >= 79.6) { 
	         arrLetter[i] = 'B';
		 countB++;
		
        }    
        else if (arrNumber[i] >= 69.6) {
		arrLetter[i] = 'C';
		countC++;
		
        }        
        else if (arrNumber[i] >= 59.6) {
		arrLetter[i] = 'D';
		countD++;
		
        }           
        else {
	       arrLetter[i] = 'F';
	       countF++;
	
        }
  	
i++;
}//loop delimiter
inc.close();

cout << "STUDENT ID" << setw(14) << "NUMERIC GRADE" << setw(14) << "LETTER GRADE" << endl;

    for (int c = 0; c < i; c++) 
    {
      cout << arrSSN[c] << setw(10) << fixed << setprecision(2) << arrNumber[c] <<  setw(10) << arrLetter[c] << endl;
    }

cout << "Number of As:" << countA << endl;
cout << "Number of Bs:" << countB << endl;
cout << "Number of Cs:" << countC << endl;
cout << "Number of Ds:" << countD << endl;
cout << "Number of Fs:" << countF << endl;

//calculate overall mean
mean = calcMean(arrNumber, size);
cout <<"Class Average: " << fixed << setprecision(2) << mean << endl;


//determine highest and lowest  

float maximum = 0;
float minimum = 100;
for (int i=0; i < size; i++) {

if (arrNumber[i] < minimum)  
	minimum = arrNumber[i];
if (arrNumber[i] > maximum)
	maximum = arrNumber[i];


}
cout << "Maximum: " << maximum << endl;
cout << "Minimum: " << minimum << endl;

return 0;
}
//*************************************calcMean*********************************
//Name: calcMean
//Parameters:  arr catches arrNumber
//	       index catches size
//Return:  mean
//
//
//******************************************************************************
float calcMean(float arr[], int index) {
 float sum = 0;
 float mean;
   for (int i = 0; i < index; i++) {
       sum += arr[index];
       mean = sum/index;
   }
cout << mean;
return mean;
}


Output:

0.00Class Average: 0.00


I cannot figure out why it is not computing the class average and instead reports a zero.
badkaykay (96)
Perhaps it is because I close the data file too early?
closed account (DSLq5Di1)
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   for (int i = 0; i < index; i++) {
       sum += arr[i];
       mean = sum/index;
   }
   mean = sum/index;
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