How to paint binary tree in red-black

Question

I have already created binary tree, and i have to paint every node in red or black to make red-black tree.

struct node {
    string name;
    int year;
    int num;

    node *right = NULL, *node = NULL;
    string color;
    node* parent = NULL;
};

class bTree {

    node* root;
    int avarage = 0;
    int count = 0;
public: 
    node* getRoot() { return root; }
    bTree() { root = NULL; };
    void create(string Name, int Year, int Num);
    void add(string Name, int Year, int Num);
    void paint(node* temp);
}