How to call a private member function inside main()

[rnima]

I am trying to call a private member function inside main()

class Rectangle {
private:
    int     size;
    void    computeSize();
};

int main () 
{
   Rectangle rect;
   // I want to call computeSize() here // 

}

[Thomas1965]

You can't. Private members can only be accessed by members of the class.
That's the point of private.

[seeplus]

Why is computeSize() private and not public?