Console output giving unexpected number after a simple calculation? c++

Question

This is an assignment that I am doing for university and I have not had many problems with assignments up until this point. I would expect my program to be working properly as I would expect it to but when going through the console output, I am getting a weird calculation. This program takes input from a text file and calculates the grade for three students who took four tests. Please let me know what I have done wrong. Thank you.

My code:

#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <fstream>
using namespace std;

//global variables
const int STUDENT = 3;
const int TEST = 4;

//function initializers
void getTests(double[STUDENT][TEST]);
double totalTests(double[STUDENT][TEST]);
double averageTests(double[STUDENT][TEST]);
void averageEachTest(double[STUDENT][TEST]);
void averageEachStudent(double[STUDENT][TEST]);
double getHighest(double[STUDENT][TEST]);
void getHighestOfEachTest(double[STUDENT][TEST]);
void getLowestOfEachTest(double[STUDENT][TEST]);
void report(double[STUDENT][TEST]);

//main
int main()
{
    double testScores[STUDENT][TEST]{};

    getTests(testScores);
    report(testScores);

    return 0;
}

//**************************************

void getTests(double testScores[STUDENT][TEST])
{
    fstream inFile;
    inFile.open("test.txt");
    if (!inFile)
    {
        exit(1);
    }

    for (int student = 0; student < STUDENT; student++)
    {
        for (int test = 0; test < TEST; test++)
        {
            inFile >> testScores[student][test];
        }
    }
}

//*****************************************

double totalTests(double testScores[STUDENT][TEST])
{
    double total = 0;

    for (int s = 0; s < STUDENT; s++)
    {
        for (int t = 0; t < TEST; t++)
        {
            total += testScores[s][t];
        }

    }

    return total;
}

//**************************************

double averageTests(double testScores[STUDENT][TEST])
{
    double average = 0.0, total = 0.0;

    for (int s = 0; s < STUDENT; s++)
    {
        for (int t = 0; t < TEST; t++)
        {
            total += testScores[s][t];
        }
    }
    
    average = total / (static_cast <double> (STUDENT) * TEST);

    return average;
}

//*************************************

void averageEachTest(double testScores[STUDENT][TEST])
{
    double average = 0.0, total = 0.0;

    cout << "Average for each test:\n";

    for (int t = 0; t < TEST; t++)
    {
        total = 0;
        for (int s = 0; s < STUDENT; s++)
        {
            total += testScores[s][t];
            average = total / STUDENT;
        }
        cout << "Average score of test " << t + 1
            << ": " << average << endl;
    }
}

//******************************************

void averageEachStudent(double testScores[STUDENT][TEST])
{
    double average = 0.0, total = 0.0;

    cout << "Average for each student:\n";

    for (int s = 0; s < TEST; s++)
    {
        total = 0;
        for (int t = 0; t < STUDENT; t++)
        {
            total += testScores[s][t];
            average = total / STUDENT;
        }
        cout << "Average score of student " << s + 1
            << ": " << average << endl;
    }
}

//*************************************

double getHighest(double testScores[STUDENT][TEST])
{
    double highest = testScores[0][0];

    for (int s = 0; s < STUDENT; s++)
    {
        for (int t = 0; t < TEST; t++)
        {
            if (testScores[s][t] > highest)
            {
                highest = testScores[s][t];
            }
        }
    }
    return highest;
}

//************************************

void getHighestOfEachTest(double testScores[STUDENT][TEST])
{

    cout << "Highest for each test:\n";
    for (int t = 0; t < TEST; t++)
    {
        double highest = testScores[0][t];
        for (int s = 0; s < STUDENT; s++)
        {
            if (testScores[s][t] > highest)
            {
                highest = testScores[s][t];
            }
        }
        cout << "Highest score for test " << t + 1
            << ": " << highest << endl;
    }
}

//**************************************

void getLowestOfEachTest(double testScores[STUDENT][TEST])
{
    cout << "Lowest for each test:\n";
    for (int t = 0; t < TEST; t++)
    {
        double lowest = testScores[0][t];
        for (int s = 0; s < STUDENT; s++)
        {
            if (testScores[s][t] < lowest)
            {
                lowest = testScores[s][t];
            }
        }
        cout << "Lowest score for test " << t + 1
            << ": " << lowest << endl;
    }
}

//*****************************************

void report(double testScores[STUDENT][TEST])
{
    cout << fixed << showpoint << setprecision(2);

    double totalOfAllTests = totalTests(testScores);
    cout << "Total of all tests: " << totalOfAllTests << endl;
    cout << "Press enter to continue.\n";
    cin.get();

    double avgOfAllTests = averageTests(testScores);
    cout << "Average of all tests: " << avgOfAllTests << endl;
    cout << "Press enter to continue.\n";
    cin.get();

    averageEachTest(testScores);
    cout << "Press enter to continue.\n";
    cin.get();

    averageEachStudent(testScores);
    cout << "Press enter to continue.\n";
    cin.get();

    double highest = getHighest(testScores);
    cout << "Highest of all tests: " << highest << endl;
    cout << "Press enter to continue.\n";
    cin.get();

    getHighestOfEachTest(testScores);
    cout << "Press enter to continue.\n";
    cin.get();

    getLowestOfEachTest(testScores);
    cout << "Press enter to continue.\n";
    cin.get();
}

//*******************************************

the text file contents:

70
80
90
75
85
90
60
80
80
90
80
75

The console output:

Total of all tests: 955.00
Press enter to continue.

Average of all tests: 79.58
Press enter to continue.

Average for each test:
Average score of test 1: 78.33
Average score of test 2: 86.67
Average score of test 3: 76.67
Average score of test 4: 76.67
Press enter to continue.

Average for each student:
Average score of student 1: 80.00
Average score of student 2: 78.33
Average score of student 3: 83.33
Average score of student 4: -92559631349317830736831783200707727132248687965119994463780864.00
Press enter to continue.

Highest of all tests: 90.00
Press enter to continue.

Highest for each test:
Highest score for test 1: 85.00
Highest score for test 2: 90.00
Highest score for test 3: 90.00
Highest score for test 4: 80.00
Press enter to continue.

Lowest for each test:
Lowest score for test 1: 70.00
Lowest score for test 2: 80.00
Lowest score for test 3: 60.00
Lowest score for test 4: 75.00
Press enter to continue.


C:\Users\antmc\source\repos\REALAssignment20_StudentTestScores_functions+arrays\x64\Debug\REALAssignment20_StudentTestScores_functions+arrays.exe (process 34320) exited with code 0.
Press any key to close this window . . .

Answer 1

You are seeing an uninitialized value.

cout << "Average score of student " << s + 1
        << ": " << average << endl;

If you look at the for loop defining s then you'll see it is tested against TEST. You have got the upper condition for you two loops backwards.