graph using adjacency list

[ITNoob]

#include<iostream>

using namespace std;

class Graph{
public:
void addVertex(int vertex);
void display();
TCSGraph(){

head = NULL;
}
~Graph(){}

private:
struct ListNode
{
string name;
struct ListNode *next;
};

ListNode *head;
};

void Graph::addVertex(int vertex){
ListNode *newNode;
ListNode *nodePtr;
string vName;

for(int i = 0; i < vertex ; i++ ){
cout << "what is the name of the vertex"<< endl;
cin >> vName;
newNode = new ListNode;
newNode->name = vName;
newNode->next = NULL;

if (!head)
head = newNode;
else{
nodePtr = head;
while(nodePtr->next)
nodePtr = nodePtr->next;

nodePtr->next = newNode;

}
}
}

void Graph::display(){
ListNode *nodePtr;
nodePtr = head;

while(nodePtr){
cout << nodePtr->name<< endl;
nodePtr = nodePtr->next;
}
}

void displayMenu(){
cout << endl << endl;
cout << " 1. Add a vertice" << endl;
cout << " 2. Displaying a graph by printing out the adjacency lists" << endl;
cout << " 0. Quit" << endl;
cout << endl;
cout << "Please enter your option: ";
}

int main(){

int choice;
int vertex;
bool done = false;

do{
displayMenu();
cin >> choice;
TCSGraph g;

if(choice==1){
cout << " how many vertex u wan to add" << endl;
cin >> vertex;
g.addVertex(vertex);
}
else if (choice==2){
g.display();
}
}while(!done);

return 0;
}