Thread: Two errors I don't know how to deal with.

Hello. I am getting the following two errors on the code below, and I don't know how to fix them. Can someone help me please? The function is designed to calculate the weighted average of homework, quiz, and test grades read in from an input file, as well as a later function that calculates the total average after a dropped homework grade.

The errors are:

Code:

1>MSVCRTD.lib(crtexew.obj) : error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup
1>C:\Users\Trey\documents\visual studio 2010\Projects\Program 5\Debug\Program 5.exe : fatal error LNK1120: 1 unresolved externals

The program is as follows:

Code:

// Trey Brumley
// CMPS 1043-101
// December 3, 2012
// Program 5 - Arrays
// ==================

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

// Prototypes
void header();
void totalAverage(int x, int y, int z);
void droppedGrade();
void droppedGradeAverage(int x, int y, int z);

// Main Function
int main()
{
    ifstream infile;
    infile.open("input.txt");
    ofstream outfile;
    outfile.open("output.txt");

    header();
    int homework[7], quiz[9], test[3], sum1=0, sum2=0, sum3=0;
    for (int i = 0; i<7; i++)
    {
        infile >> homework[i];
        sum1 += homework[i];
    }
    for (int i = 0; i<9; i++)
    {
        infile >> quiz[i];
        sum2 += quiz[i];
    }
    for (int i = 0; i<3; i++)
    {
        infile >> test[i];
        sum3 += test[i];
    }

    totalAverage(sum1, sum2, sum3);
    droppedGrade();

    return 0;
}

// Prints a header on output file
void header()
{
    ofstream outfile;
    outfile.open("output.txt");

    outfile << "Trey Brumley" << endl;
    outfile << "CMPS 1043-101" << endl;
    outfile << "December 3, 2012" << endl;
    outfile << "Program 5 - Arrays" << endl;
    outfile << "==================" << endl << endl;

    return;
}

// Finds the weighted and total average of each category
void totalAverage(int x, int y, int z)
{
    ofstream outfile;
    outfile.open("output.txt");
    
    double a, b, c, d, e, f, g;

    a = x/7;
    b = y/9;
    c = z/3;
    d = a*0.15;
    e = b*0.25;
    f = c*0.60;
    g = d+e+f;

    outfile << "The average for Homework Grades is " << setprecision(1) << a << "." << endl;
    outfile << "The weighted average of homework (15%) amounts to " << setprecision(1) << d << "." << endl;
    outfile << "The average for Quiz Grades is " << setprecision(1) << b << "." << endl;
    outfile << "The weighted average of quizzes (25%) amounts to " << setprecision(1) << e << "." << endl;
    outfile << "The average for Test Grades is " << setprecision(1) << c << "." << endl;
    outfile << "The weighted average of tests (60%) amounts to " << setprecision(1) << f << "." << endl;

    outfile << "The total weighted average of all grades is " << setprecision(1) << g << "." << endl;

    return;
}

void droppedGrade()
{
    ifstream infile;
    infile.open("input.txt");
    ofstream outfile;
    outfile.open("output.txt");

    int x = 100;
    int sum4=0, sum5=0, sum6=0, sum7=0;
    int homework2[7], quiz2[9], test2[3];
    
    for (int i = 0; i<7; i++)
    {
        infile >> homework2[i];
        if ( homework2[i]<x)
            x = homework2[i];
        sum4 += homework2[i];
    }
    sum7=sum4-x;
    for (int i = 0; i<9; i++)
    {
        infile >> quiz2[i];
        sum5 += quiz2[i];
    }
    for (int i = 0; i<3; i++)
    {
        infile >> test2[i];
        sum6 += test2[i];
    }

    droppedGradeAverage(sum7, sum5, sum6);

    return;
}

void droppedGradeAverage(int x, int y, int z)
{
    ofstream outfile;
    outfile.open("output.txt");
    
    double a, b, c, d, e, f, g;

    a = x/6;
    b = y/9;
    c = z/3;
    d = a*0.15;
    e = b*0.25;
    f = c*0.60;
    g = d+e+f;

    outfile << "The average for Homework Grades after dropping the lowest grade is " << setprecision(1) << a << "." << endl;
    outfile << "The weighted average of homework (15%) amounts to " << setprecision(1) << d << "." << endl;
    outfile << "The average for Quiz Grades is " << setprecision(1) << b << "." << endl;
    outfile << "The weighted average of quizzes (25%) amounts to " << setprecision(1) << e << "." << endl;
    outfile << "The average for Test Grades is " << setprecision(1) << c << "." << endl;
    outfile << "The weighted average of tests (60%) amounts to " << setprecision(1) << f << "." << endl;

    outfile << "The total weighted average of all grades minus the dropped homework grade is " << setprecision(1) << g << "." << endl;

    return;
}

K, so the errors are gone, but now it's not printing my header, and the values the program is turning up are values along the lines of 7e+001, 2e+001, etc. How do I fix those?

There are a couple of problems. Firs when you open an output file stream using the default open mode you will truncate (erase) the file when opening it. And because you are opening this file in every function you will erase the contents in every file.

Another problem is that you are opening your file in main() and then re-opening the same file in your functions, you really should only open the same file once. You should learn to properly pass the open stream to your functions. You also should always check that your files open successfully.

Also what is contained in your input.txt file?

Jim

Thanks for the help in getting it to print. It does print now but the problem is, I'm getting the wrong results. The data I should be replicating shows that the first seven numbers should average out to 71.4, and it averages directly to 71. I don't see how it's doing that. The other two seem to be reading just fine, except they too are rounding down.

The answers I'm getting for the straight-up averages are 71, 91, and 89. I SHOULD be getting exact answers, which is why the setprecision(1), which should lead to 71.4, 91.7, and 89.7. What is causing this error in mathematics?

K, got that one figured out, by adding a .0 after the divisors, but now there's one more problem and I think I'll be done. The final answer I should be receiving is 87.5. I'm receiving 87.4. The outside mathematics using my above values that I should be getting (which I am now), I should end up with 87.455 as an average, which rounds up to 87.5.

C/C++ doesn't automatically round up. If you want to round up you will need to do that yourself, mathematically.

Jim