Need Help: Variable transfer to other class

I'm new to c++ and I'm writing a 2D game with SDL right now and i want to make a game where you're being followed by a tornado. So you can move ans the tornado move towards you. But when I use the x coordinates of the boy in the move section of the tornado it sais that te xboy is not declared so I can i do that

Here's the code so far

Code:

///The boy that will move around on the screen
class Boy
{
    private:
    //The X and Y offsets of the boy
    int xboy, yboy;
    
    //The velocity of the boy
    int xVelboy, yVelboy;
    
    public:
    //Initializes the variables
    Boy();
    
    //Takes key presses and adjusts the boy's velocity
    void handle_input();
    
    //Moves the boy
    void move();
    
    //Shows the boy on the screen
    void show();
};

Boy::Boy()
{
    //Initialize the offsets
    xboy = 40;
    yboy = 40;
    
    //Initialize the velocity
    xVelboy = 0;
    yVelboy = 0;
}

after this, I have the other functions and then I create the Tornado class

Code:

//The Tornado that will move around on the screen
class Tornado
{
    private:
    //The X and Y offsets of the Tornado
    int xtor, ytor;
    
    //The velocity of the Tornado
    int xVeltor, yVeltor;
    
    public:
    //Initializes the variables
    Tornado();
    
    //Moves the Tornado
    void move();
    
    //Shows the Tornado on the screen
    void show();
};

Tornado::Tornado()
{
    //Initialize the offsets
    xtor = 800;
    ytor = 400;
    
    //Initialize the velocity
    xVeltor = 0;
    yVeltor = 0;
}


void Tornado::move()
{
    
    //Move the Tornado left or right
    xtor += xVeltor;
    
    //If the Tornado is at the right side of the boy
    if(  xtor > xboy  )
    {
        //move to the left
        xVeltor = -5;    
    }
      
    //If the Tornado is at the left side of the boy
    if(  xtor < xboy  )
    {
        //move to the left
        xVeltor = 5;    
    } 
    
    //Move the Tornado up or down
    ytor += yVeltor;
    
    //If the Tornado is above the boy
    if(  ytor < yboy  )
    {
        //move to the left
        yVeltor= 5;    
    } 
   
   //If the Tornado is under the boy
    if(  ytor > yboy  )
    {
        //move to the left
        yVeltor = -5;    
    } 

}

The game works when I place a number in stead of xboy and yboy but then the tornado moves towards that point and then stays right there.

Please help me

Well you could make Tornado have a pointer to the Boy object. Then the Tornado could call code like boy->get_xboy() for example. Food for thought:

Code:

class Boy {
private:
    int xboy, yboy;
public:
    int get_xboy() { return xboy; }
    int get_yboy() { return yboy; }
};

class Tornado {
private:
    Boy *boy;
public:
    void setBoy(Boy *b) { boy = b; }
    void move();
};

void Tornado::move() {
    int xboy = boy->get_xboy();
    int yboy = boy->get_yboy();
    // ...
}

// somewhere else, maybe main()
Boy b;
Tornado t;
t.setBoy(&b);

t.move();  // now knows about xboy