Nothing prints; do I need a main or should it work without it, theoretically?

Question

I'd hate to ask this but I've been trying this for HOURS and I can't figure it out. I'm brand new to C++ and can't figure out why the sprintf_s won't put anything out at the end (or both of them for that matter). Basically, nothing happens in Visual Studio 2019 except the window pops up. I know it's a simple solution but I am going crazy trying to figure it out. Also, do I HAVE to have a main or should it work without it? Ok, also, does my constructor look ok? I have the green squiggly under it and not sure how to fix it or if I can ignore that. I appreciate all the help I can get! Thank you!

//#include "stdafx.h" - commented out as I think this version of VS does 
//this automatically (I looked under precompiled headers and it was listed as "Precompiled Header File"
//and it wouldn't work unless I commented it out

#include <iostream>

using namespace std;

// Base Entree class
class Entree
{
protected:
    char _entree[10];
public:
    const char* getEntree()
    {
        return _entree;
    }
};


// Base Side class
class Side
{
protected:
    char _side[10];
public:
    char* getSide()
    {
        return _side;
    }
};

class Drink
{
protected:
    char _drink[10];
public:
    Drink()
    {
        cout << "\n Fill cup with soda" << endl;
        strcpy_s(_drink, "soda");
    }
    char* getDrink()
    {
        return _drink;
    }
};

// ADDED CODE:

class ComboMeal
{
private:
    Entree* entree;
    Side* side;
    Drink* drink;
    char _bag[100];

public:
    ComboMeal(const char* type)
        {
        sprintf_s(_bag, "/n %s meal combo: ", type);
        }
        void setEntree(Entree * e)
        {
            entree = e;
        }
        void setSide(Side * s)
        {
            side = s;
        }
        void setDrink(Drink * d)
        {
            drink = d;
        }
        const char* openMealBag()
        {
            sprintf_s(_bag, "%s, %s, %s, %s", _bag, entree->getEntree(), side->getSide(), drink->getDrink());
            return _bag;
        }
};
int main()
{   
}

Answer 1

As it's been said in the comments, in C++ the code that's executed is the one in the main function. Constructors are called when objects of the correspondent class are created, so you should at least have something like this:

int main(){
    ComboMeal combo("my type one");
    return 0;
}

A more complete example would be:

int main(){
    ComboMeal combo("my type one");
    combo.setEntree(new Entree);
    combo.setSide(new Side);
    combo.setDrink(new Drink);
    cout << combo.openMealBag() << endl;
    return 0;
}

(Of course this will print garbage, because the values within the new objects are not set)