cannot conver 'node*' to 'node**'

[HeavyDrugs]

I'm new to pointers and can't solve this error "cannot conver 'node*' to 'node**'". What is the problem here?

#include <iostream>

using namespace std;

    struct node{
        int num;
        node *next;
    };

    bool arTuscias(node *head);
    char menu();
    node* nodeKurimas(int num);
    int size=0;

    void sukurimasPradzioje(node *&head, node *&tail, int num);
    void spausdinimas(node *dabartinis);

    void sukurimasReplace(node **dabartinis, int num, int pos);


int main()
{
    node *head = NULL;
    node *tail = NULL;
    char pasirinkimas;
    int num;
    int pos;

    do{
    pasirinkimas = menu();

        switch(pasirinkimas){
            case '1':   cout<<"Iveskite skaiciu: ";
                        cin>>num;
                        sukurimasPradzioje(head,tail,num);
                        break;

            case '2':   cout<<"Spausdinamas visas sarasas: "<<endl;
                        spausdinimas(head);
                        break;

            case '3':   cout<<"Iveskite elemento pozicija"<<endl;
                        cin>>pos;
                        cout<<"Iveskite elementa"<<endl;
                        cin>>num;
                        sukurimasReplace(head,num,pos);
                        break;



            default: cout<<"Toks pasirinkimas neegzistuoja"<<endl;

        };

    }while(pasirinkimas !='7');

    return 0;
}

    bool arTuscias(node *head){
        if(head == NULL)
            return true;
        else
            return false;
    }

    node* nodeKurimas(int num){
        node* temp = new node();
        temp->num=num;
        temp->next=NULL;
        return temp;
    }

    char menu(){
        char pasirinkimas;
        cout<<endl<<"Pasirinkite kokia funkcija norite atlikti"<<endl<<
        "1. Creates linked list"<<endl<<
        "2. Prints linked list"<<endl<<
        "3. Inserts an element to a specified position "<<endl<<
        
        cin>>pasirinkimas;

        return pasirinkimas;
    }
    void sukurimasPradzioje(node *&head, node *&tail, int num){
        if(arTuscias(head)){
        node *temp = new node;
        temp->num = num;
        temp->next = NULL;
        head = temp;
        tail = temp;
        }
    else{
        node *temp = new node;
        temp->num = num;
        temp->next = NULL;
        tail->next = temp;
        tail = temp;
        }
        size++;
    }

    void sukurimasReplace(node **dabartinis, int num, int pos){


    // This condition to check whether the
    // postion given is valid or not.
    if (pos < 1 || pos > size + 1)
        cout << "Invalid postion!" << endl;
    else {

        // Keep looping until the pos is zero
        while (pos--) {

            if (pos == 0) {

                // adding Node at required postion
                node* temp = nodeKurimas(num);

                // Making the new Node to point to
                // the old Node at the same position
                temp->next = *dabartinis;

                // Changing the pointer of the Node previous
                // to the old Node to point to the new Node
                *dabartinis = temp;
            }
            else
              // Assign double pointer variable to point to the
              // pointer pointing to the address of next Node
              dabartinis = &(*dabartinis)->next;
        }
        size++;
    }
}

    void spausdinimas(node *dabartinis){
        if(arTuscias(dabartinis))
            cout<<"Sarasas tuscias"<<endl;
        else{
            cout<<"Saraso elementai:"<<endl;
            while(dabartinis != NULL){
                cout<<dabartinis->num<<endl;
                dabartinis = dabartinis->next;
            }
        }
    }

[nuderobmonkey]

You pass a pointer as an argument where a 'pointer to pointer' is required. Solution: pass as '&head' instead o 'head'in line 46.

Beside some small other errors, your code is a good example why it's not good dumping the std library stuff into the global namespace: You cannot anymore use 'size' because it's still defined somewhere by including the <iostream> header. So don't use 'using namespace std'..