Cannot call bool function with array program

I am new to C++ (and coding in general) and am learning about arrays. The purpose of the assignment was to have a user input square parameters and numbers to fill each row. My program's job was to take user input numbers and validate sums against rows, columns, and diagonals.

Well, originally when I wrote the program in main, it worked. However, I have to get the program to run in a bool function and return a false if it fails. For the life of me I cannot figure out a way to make it work. I keep getting fatal errors for 1 unresolved externals. Can someone please help me? I've exhausted all resources.

Thank you.

    #include <iostream>
   #include <iomanip>
   #include <fstream>

   using namespace std;

   bool validateSums(int, int);

   int main()
   {
    int row,
        square[10][10];
    bool match;

    cout << "Enter the size of your square by the # of rows (e.g. 3 would yield a 3x3 square).\n"
        << "Please keep the # to 10 or below." << endl;
    cin >> row;

    if (row >= 1 && row <= 10)
    {
        cout << "Your square will be " << row << "  x " << row << " big." << endl;

        for (int index = 0; index < row; index++)
        {
            cout << "List " << row << " numbers for row " << (index + 1)
                << " separated by a space." << endl;
            for (int colindex = 0; colindex < row; colindex++)
            {
                cin >> square[index][colindex];
            }
        }
        cout << "You listed \n";
        for (int index = 0; index < row; index++)
        {
            for (int colindex = 0; colindex < row; colindex++)
            {
                cout << setw(2) << square[index][colindex] << " ";
            }
            cout << endl;
        }

        match = validateSums(row, square);
        cout << match << endl;
    }
    else
    {
        cout << "You must enter a # between 1-10." << endl;
    }

    return 0;
   }

   bool validateSums(int row, int square[][10])
   {
    //summation of 1st row
    int total = 0,
        compareTotal = 0;

    for (int colindex = 0; colindex < row; colindex++)
    {
        total += square[0][colindex];
    }

    //calculation of sum for rest of rows while comparing to total
    for (int index = 1; index < row; index++)
    {
        for (int colindex = 0; colindex < row; colindex++)
        {
            compareTotal += square[index][colindex];
        }

        if (compareTotal != total)
        {
            cout << "The rows entered do not match." << endl;
            break;
            return false;
        }
        else
        {
            compareTotal = 0;
        }
    }

    //summation of 1st column
    total = 0;
    for (int index = 0; index < row; index++)
    {
        total += square[index][0];
    }
    cout << "Sum of column 1 is " << total << endl;

    //calculation of sum for rest of columns while comparing to total
    compareTotal = 0;
    for (int colindex = 1; colindex < row; colindex++)
    {
        for (int index = 0; index < row; index++)
        {
            compareTotal += square[index][colindex];
        }

        if (compareTotal != total)
        {
            cout << "The columns entered do not match." << endl;
            break;
            return false;
        }
        else
        {
            compareTotal = 0;
        }
    }

    //summation of 1st diagonal
    total = 0;
    for (int index = 0; index < row; index++)
    {
        total += square[index][index];
    }
    cout << "Sum of diagonal 1 is " << total << endl;

    //calculation of sum of the other diagonal
    compareTotal = 0;
    for (int index = 0; index < row; index++)
    {
        compareTotal += square[index][row - 1 - index];
    }
    if (compareTotal != total)
    {
        cout << "The diagonals entered do not match." << endl;
        return false;
    }
}

Error message (pasted from comment):

1>------ Build started: Project: ConsoleApplication18, Configuration: Debug Win32 ------
1>MSVCRTD.lib(crtexe.obj) : error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup
1>C:\Users\Sasha\Documents\CS 161\Assignment 4\ConsoleApplication18\Debug\ConsoleApplication18.exe : fatal error LNK1120: 1 unresolved externals
==========  Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========