Working conversion from list to matrix

#include <cmath>
using namespace std;

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

struct list {
    node* head;
    node* tail;
};

void add_node(int value, list* listx) {
    node *temp = new node;
    temp->data = value;
    temp->next = NULL;
    if(listx->head == NULL) {
        listx->head = temp;
        listx->tail = temp;
        temp = NULL;
    }
    else {
        listx->tail->next = temp;
        listx-> tail = temp;
    }
}

void add_first(int value, list* listx) {

    node *temp = new node;

    temp->data = value;

    temp->next = listx->head;

    listx->head = temp;

}

void display(list* listx) {
    node *temp = new node;
    temp = listx->head;
    while(temp != NULL) {
        cout << "(" << (temp->data + 1) << ")";
        if(temp->next != NULL) {
            cout << ", ";
        }
        temp = temp->next;
    }
}


int main() {

    int n;
    cin >> n;

    list listar[n];



    for(int i = 0; i < n; i++) {

        list *listx = new list;
        listx->head = NULL;
        listx->tail = NULL;

        int inserted;
        for(cin >> inserted; inserted != 777; cin >> inserted) {
            if(inserted < 0) {
                add_first(abs(inserted - 1), listx);
            } else {
                add_node(inserted - 1, listx);
            }
        }
        listar[i] = *listx;

    }

    cout << "Inserted Graph: " << endl;
    cout << "----------------" << endl;

    for(int i = 0; i < n; i++) {
        cout << "(" << i + 1 << "): ";
        display(&listar[i]);
        cout << endl;
    }

    cout << "---------------" << endl;
    cout << "Converting to matrix..." << endl;

    bool matrix[n][n];

    for(int i = 0; i < n; i++) {

        bool row[n];

        for(int j = 0; j < n; j++) {

            row[i] = false;

        }

        list *list_i = &listar[i];

        for(node *nodex = list_i->head; nodex != NULL; nodex = nodex->next) {

            row[nodex->data] = true;

        }

        memcpy(matrix + i, row, sizeof(row));

    }

    cout << "-----------" << endl;
    cout << "Converted matrix: " << endl;

    cout << "  |";
    for(int i = 0; i < n; i++) {

        cout << " " << i + 1 << " |";

    }
    cout << endl;
    for(int i = 0; i < n; i++) {

        cout << i + 1 << " |";
        for(int j = 0; j < n; j++) {

            cout << " " << (matrix[i][j] ? 1 : 0) << " |";

        }
        cout << endl;

    }




    return 0;
}