Help using arrays

[SlenderMan]

The program reads in the student id and their 2 test grades and 7 homework grades. Then it calculates their final grade. IT is supposed to read up to 30 students.

I wrote the program which works but does not do exactly what is wanted. Im lost and have no idea how to start changing it. Can someone lead me in the right direction? My teacher had these comments when i submitted.

works but the output miss the last two students; the program can't process 30 students, but only 9; the array of students should not be named as "length"; getinput function does not use for-loop to work with test/hw arrays, but repeats the code; process function does not use the second parameter size, not use for-loop, but repeat code 7 times; most variables are global;

Text file it reads from:

123456789 77.2 88.3 22 28 35 45 33 35 40
234567890 97.5 90 25 30 38 48 34 35 50
345678901 82.4 77.5 22.5 27 35.5 44 35 33 48
456789012 65.5 67 20 25 28 40 27 25 35
567890123 79.5 82 25 30 32 47 30 33 46
678901234 90 86.5 25 30 40 46 34 35 50
789012345 77 82.2 25 30 36 46 33 32.5 47
890123456 67.7 72.5 23 28 35 44 30 30 44
901234567 76.5 83.4 25 29 38 49 35 35 49

#include <iostream>
#include <conio.h>
#include <fstream>
#include <iomanip>
using namespace std;

struct SStudent
{
	int id;
	double test1, test2, hw1, hw2, hw3, hw4, hw5, hw6, hw7;
};

int getInput(SStudent [], int);
void process(SStudent [], int);
void display(const SStudent [], int);

double testAvg1, testAvg2, testAvg3, testAvg4, testAvg5, testAvg6, testAvg7,
		   hwAvg1, hwAvg2, hwAvg3, hwAvg4, hwAvg5, hwAvg6, hwAvg7,
		   finalScore1, finalScore2, finalScore3, finalScore4, finalScore5, finalScore6, finalScore7;

char grade1, grade2, grade3, grade4, grade5, grade6, grade7;

int countA, countB, countC, countD, countE;

int main()
{
	SStudent length[9];

	getInput(length, 9);
	process(length, 9);
	display(length, 9);
	_getch();
}

int getInput(SStudent students[], int size)
{
	ifstream inFile;
	inFile.open("scores.txt");
	int count = 0;
	if(!inFile)
	{
		cout << "Can't open input file\n";
		_getch();
		exit(1);
	}

	for(int i = 0; i < size; ++i)
	{
		inFile >> students[i].id >> students[i].test1 >> students[i].test2 
			>> students[i].hw1 >> students[i].hw2 >> students[i].hw3 
			>> students[i].hw4 >> students[i].hw5 >> students[i].hw6
			>> students[i].hw7;

		count = count + 1;
	}
	return count;
}

void process(SStudent students[], int size)
{	
	testAvg1 = ((students[0].test1 + students[0].test2) / 200) * 100;
	testAvg2 = ((students[1].test1 + students[1].test2) / 200) * 100;
	testAvg3 = ((students[2].test1 + students[2].test2) / 200) * 100;
	testAvg4 = ((students[3].test1 + students[3].test2) / 200) * 100;
	testAvg5 = ((students[4].test1 + students[4].test2) / 200) * 100;
	testAvg6 = ((students[5].test1 + students[5].test2) / 200) * 100;
	testAvg7 = ((students[6].test1 + students[6].test2) / 200) * 100;

	hwAvg1 = ((students[0].hw1 + students[0].hw2 + students[0].hw3 + students[0].hw4 + students[0].hw5 + students[0].hw6 + students[0].hw7) / 265) * 100;
	hwAvg2 = ((students[1].hw1 + students[1].hw2 + students[1].hw3 + students[1].hw4 + students[1].hw5 + students[1].hw6 + students[1].hw7) / 265) * 100;
	hwAvg3 = ((students[2].hw1 + students[2].hw2 + students[2].hw3 + students[2].hw4 + students[2].hw5 + students[2].hw6 + students[2].hw7) / 265) * 100;
	hwAvg4 = ((students[3].hw1 + students[3].hw2 + students[3].hw3 + students[3].hw4 + students[3].hw5 + students[3].hw6 + students[3].hw7) / 265) * 100;
	hwAvg5 = ((students[4].hw1 + students[4].hw2 + students[4].hw3 + students[4].hw4 + students[4].hw5 + students[4].hw6 + students[4].hw7) / 265) * 100;
	hwAvg6 = ((students[5].hw1 + students[5].hw2 + students[5].hw3 + students[5].hw4 + students[5].hw5 + students[5].hw6 + students[5].hw7) / 265) * 100;
	hwAvg7 = ((students[6].hw1 + students[6].hw2 + students[6].hw3 + students[6].hw4 + students[6].hw5 + students[6].hw6 + students[6].hw7) / 265) * 100;

	finalScore1 = (testAvg1 * .60) + (hwAvg1 * .40);
	finalScore2 = (testAvg2 * .60) + (hwAvg2 * .40);
	finalScore3 = (testAvg3 * .60) + (hwAvg3 * .40);
	finalScore4 = (testAvg4 * .60) + (hwAvg4 * .40);
	finalScore5 = (testAvg5 * .60) + (hwAvg5 * .40);
	finalScore6 = (testAvg6 * .60) + (hwAvg6 * .40);
	finalScore7 = (testAvg7 * .60) + (hwAvg7 * .40);

	if (finalScore1 < 60)
	{
		grade1 = 'E';
		countE += 1;
	}
	else if (finalScore1 > 60 && finalScore1 <= 69.99)
	{
		grade1 = 'D';
		countD += 1;
	}
	else if (finalScore1 > 69.99 && finalScore1 <= 79.99)
	{
		grade1 = 'C';
		countC += 1;
	}
	else if (finalScore1 > 79.99 && finalScore1 <= 89.99)
	{
		grade1 = 'B';
		countB += 1;
	}
	else
	{
		grade1 = 'A';
		countA += 1;
	}

//grade2
	if (finalScore2 < 60)
	{
		grade2 = 'E';
		countE += 1;
	}
	else if (finalScore2 > 60 && finalScore2 <= 69.99)
	{
		grade2 = 'D';
		countD += 1;
	}
	else if (finalScore2 > 69.99 && finalScore2 <= 79.99)
	{
		grade2 = 'C';
		countC += 1;
	}
	else if (finalScore2 > 79.99 && finalScore2 <= 89.99)
	{
		grade2 = 'B';
		countB += 1;
	}
	else
	{
		grade2 = 'A';
		countA += 1;
	}

//grade3
	if (finalScore3 < 60)
	{
		grade3 = 'E';
		countE += 1;
	}
	else if (finalScore3 > 60 && finalScore3 <= 69.99)
	{
		grade3 = 'D';
		countD += 1;
	}
	else if (finalScore3 > 69.99 && finalScore3 <= 79.99)
	{
		grade3 = 'C';
		countC += 1;
	}
	else if (finalScore3 > 79.99 && finalScore3 <= 89.99)
	{
		grade3 = 'B';
		countB += 1;
	}
	else
	{
		grade3 = 'A';
		countA += 1;
	}

//grade 4
	if (finalScore4 < 60)
	{
		grade4 = 'E';
		countE += 1;
	}
	else if (finalScore4 > 60 && finalScore4 <= 69.99)
	{
		grade4 = 'D';
		countD += 1;
	}
	else if (finalScore4 > 69.99 && finalScore4 <= 79.99)
	{
		grade4 = 'C';
		countC += 1;
	}
	else if (finalScore4 > 79.99 && finalScore4 <= 89.99)
	{
		grade4 = 'B';
		countB += 1;
	}
	else
	{
		grade4 = 'A';
		countA += 1;
	}

//grade 5
	if (finalScore5 < 60)
	{
		grade5 = 'E';
		countE += 1;
	}
	else if (finalScore5 > 60 && finalScore5 <= 69.99)
	{
		grade5 = 'D';
		countD += 1;
	}
	else if (finalScore5 > 69.99 && finalScore5 <= 79.99)
	{
		grade5 = 'C';
		countC += 1;
	}
	else if (finalScore5 > 79.99 && finalScore5 <= 89.99)
	{
		grade5 = 'B';
		countB += 1;
	}
	else
	{
		grade5 = 'A';
		countA += 1;
	}

//grade 6
	if (finalScore6 < 60)
	{
		grade6 = 'E';
		countE += 1;
	}
	else if (finalScore6 > 60 && finalScore6 <= 69.99)
	{
		grade6 = 'D';
		countD += 1;
	}
	else if (finalScore6 > 69.99 && finalScore6 <= 79.99)
	{
		grade6 = 'C';
		countC += 1;
	}
	else if (finalScore6 > 79.99 && finalScore6 <= 89.99)
	{
		grade6 = 'B';
		countB += 1;
	}
	else
	{
		grade6 = 'A';
		countA += 1;
	}

//grade 7
	if (finalScore7 < 60)
	{
		grade7 = 'E';
		countE += 1;
	}
	else if (finalScore7 > 60 && finalScore7 <= 69.99)
	{
		grade7 = 'D';
		countD += 1;
	}
	else if (finalScore7 > 69.99 && finalScore7 <= 79.99)
	{
		grade7 = 'C';
		countC += 1;
	}
	else if (finalScore7 > 79.99 && finalScore7 <= 89.99)
	{
		grade7 = 'B';
		countB += 1;
	}
	else
	{
		grade7 = 'A';
		countA += 1;
	}
}

void display(const SStudent students[], int size)
{
	ofstream outFile;
	outFile.open("grades.txt");
	outFile << fixed << showpoint;  
    outFile << setprecision(1);

    outFile << "STUDENT ID\tHW AVE\t\tTEST AVE\tFINAL SCORE\tGRADE" << endl;
	outFile << students[0].id << "\t" << hwAvg1 << "\t\t" << testAvg1 << "\t\t" << finalScore1 << "\t\t" << grade1 << endl;
	outFile << students[1].id << "\t" << hwAvg2 << "\t\t" << testAvg2 << "\t\t" << finalScore2 << "\t\t" << grade2 << endl;
	outFile << students[2].id << "\t" << hwAvg3 << "\t\t" << testAvg3 << "\t\t" << finalScore3 << "\t\t" << grade3 << endl;
	outFile << students[3].id << "\t" << hwAvg4 << "\t\t" << testAvg4 << "\t\t" << finalScore4 << "\t\t" << grade4 << endl;
	outFile << students[4].id << "\t" << hwAvg5 << "\t\t" << testAvg5 << "\t\t" << finalScore5 << "\t\t" << grade5 << endl;
	outFile << students[5].id << "\t" << hwAvg6 << "\t\t" << testAvg6 << "\t\t" << finalScore6 << "\t\t" << grade6 << endl;
	outFile << students[6].id << "\t" << hwAvg7 << "\t\t" << testAvg7 << "\t\t" << finalScore7 << "\t\t" << grade7 << endl;

	outFile << "\nNumber of A's: " << countA;
	outFile << "\nNumber of B's: " << countB;
	outFile << "\nNumber of C's: " << countC;
	outFile << "\nNumber of D's: " << countD;
	outFile << "\nNumber of E's: " << countE;
	cout << "Output file created.";
}

[cire]

#include <fstream>

const unsigned testScores = 2 ;
const unsigned hwScores = 7 ;

struct SStudent
{
	int id;
    double testScore[testScores] ;
    double hwScore[hwScores] ;
};

unsigned getInput(SStudent [], unsigned);
// ...

int main()
{
    const unsigned capacity = 30 ;
    SStudent students[capacity] ;

    unsigned nStudents = getInput(students, capacity) ;
    // ...
}


unsigned getInput(SStudent students[], unsigned maxStudents )
{
    std::ifstream in("scores.txt") ;

    unsigned count = 0 ;

    while ( count < maxStudents && (in >> students[count].id) )
    {
        for ( unsigned i=0; i<testScores; ++i )
            in >> students[count].testScore[i] ;

        for ( unsigned i=0; i<hwScores; ++i )
            in >> students[count].hwScore[i] ;

        ++count ;
    }

    return count ;
}