visual studio 2010 - C++ Fatal Error LNK1120: 1 unresolved externals

What is causing this error? I google'd it and first few solutions I found were that something was wrong with the library and the main function but both seem to be fine in my problem, I even retyped both! What could be causing this?

This might be helpful:

MSVCRTD.lib(crtexew.obj) : error LNK2019: unresolved external symbol WinMain@16 referenced in function __tmainCRTStartup

#include 
using namespace std;
int main()
{
    const double A = 15.0, 
                 B = 12.0, 
                 C = 9.0;
    double aTotal, bTotal, cTotal, total;
    int numSold;


    cout << "Enter The Number of Class A Tickets Sold: ";
    cin >> numSold;
    aTotal = numSold * A;

    cout << "Enter The Number of Class B Tickets Sold: ";
    cin >> numSold;
    bTotal = numSold * B;

    cout << "Enter The Number of Class C Tickets Sold: ";

    cin >> numSold;
    cTotal = numSold * C;

    total = aTotal + bTotal + cTotal;

    cout << "Income Generated" << endl;
    cout << "From Class A Seats $" << aTotal << endl;
    cout << "From Class B Seats $" << bTotal << endl;
    cout << "From Class C Seats $" << cTotal << endl;
    cout << "-----------------------" << endl;

    cout << "Total Income: " << total << endl;

    return 0;
}

Answer

From msdn

When you created the project, you made the wrong choice of application

type. When asked whether your project was a console application or a
windows application or a DLL or a static library, you made the wrong
chose windows application (wrong choice).

Go back, start over again, go to File -> New -> Project -> Win32
Console Application -> name your app -> click next -> click
application settings.

For the application type, make sure Console Application is selected
(this step is the vital step).

The main for a windows application is called WinMain, for a DLL is
called DllMain, for a .NET application is called
Main(cli::array ^), and a static library doesn't have a
main. Only in a console app is main called main