I'm writing a few classes for a homework assignment and I want it to be impossible for my class member functions to be called in main. If they are, I want the program to exit. How would I know when my member functions are being called? As for the class, each object represents a color in the format of <100,200,215>. Thanks for the help! 

```
class Color{

public:
    Color( unsigned red = 0, unsigned green = 0, unsigned blue = 0 );    //  ctor
    unsigned getRed() const;    //  accessor
    unsigned getGreen() const;    //  accessor
    unsigned getBlue() const;    //  accessor
    Color & setRed( unsigned red );    //  mutator
    Color & setGreen( unsigned green );    //  mutator
    Color & setBlue( unsigned blue );    //  mutator
    const Color & output() const;
private:
    unsigned myRed;
    unsigned myGreen;
    unsigned myBlue;
    static unsigned okColor(unsigned color);

}; //Class Color

int main(int argc, const char * argv[])
{

}

Color::Color( unsigned red, unsigned green, unsigned blue):
myRed(okColor(red)),myGreen(okColor(green)),myBlue(okColor(blue))
{
    //initialization list here...
}

//accessors
unsigned Color::getRed() const {return myRed;}
unsigned Color::getGreen() const {return myGreen;}
unsigned Color::getBlue() const {return myBlue;}

//mutators
Color & Color::setRed(unsigned red){
    myRed = okColor(red);
    return *this;
}

Color & Color::setGreen(unsigned green){
    myGreen = okColor(green);
    return *this;
}

Color & Color::setBlue(unsigned blue){
    myBlue = okColor(blue);
    return *this;
}

//output 
const Color & Color::output() const{

    cout << "<" << myRed << "," << myGreen << "," << myBlue << ">" << endl;
    return *this;
}

//checkers
unsigned Color::okColor(unsigned myColor){

    if (myColor > 255) {
        die("Color intensity is out of range!");
    }

    return myColor;
}

bool die(const string & msg){

    cerr << endl << "Fatal error: " << msg <<endl;
    exit(EXIT_FAILURE);
}

Color mixture( const Color & color0, const Color & color1, double weight){

    double color1Multiplier = 0;
    Color mixture;
    unsigned mixtureRed;
    unsigned mixtureBlue;
    unsigned mixtureGreen;

    color1Multiplier = 1 - weight;

    mixtureRed = (color0.getRed() * weight) + (color1.getRed() * color1Multiplier);
    mixtureBlue = (color0.getBlue() * weight) + (color1.getBlue() * color1Multiplier);
    mixtureGreen = (color0.getGreen() * weight) + (color1.getGreen() * color1Multiplier);

    mixture.setRed(mixtureRed);
    mixture.setBlue(mixtureBlue);
    mixture.setGreen(mixtureGreen);

    return mixture;
}

```