1472. design a browser history

class Node{
    public:
string data;
 Node* prev;
 Node* next;
    Node(string va)
    { 
    prev=NULL;
    next=NULL;
    data=va;
    }
};

class BrowserHistory {
public:
Node* head;
Node* temp;
    BrowserHistory(string homepage) {
       head=new Node(homepage); 
       temp=head;
    }
    
    void visit(string url) {
        Node* newi=new Node(url);
        newi->prev=temp;
        temp->next=newi;
        temp=newi;   
    }
    
    string back(int steps) {
        while(steps!=0)
        {
            if(temp->prev)
            {
                temp=temp->prev;
            }
            else{
                break;
            }
            steps--;
        }
        return temp->data;    }
    string forward(int steps) {
        while(steps!=0)
        {
            if(temp->next)
            {
                temp=temp->next;
            } else{break;}  
        steps--;}
    return temp->data;
    }
};

/**
 * Your BrowserHistory object will be instantiated and called as such:
 * BrowserHistory* obj = new BrowserHistory(homepage);
 * obj->visit(url);
 * string param_2 = obj->back(steps);
 * string param_3 = obj->forward(steps);
 */