insert at end in circular linked list code example

Example: circular linked list insertion

#include <iostream>

using namespace std;
class node
{
public:
    int data;
    node*next;
};
node*head=NULL;
void insert_begin(int a)
{
    node*temp=new node;
    temp->data=a;
    if(head==NULL)
    {
        temp->next=temp;
        head=temp;
    }
    else
    {
        node*ptr=new node;
        ptr=head;
        while(ptr->next!=head)
        {
           ptr=ptr->next;
        }
        ptr->next=temp;
        temp->next=head;
        head=temp;

    }
}
void insert_end(int a)
{
    node*temp=new node;
    temp->data=a;
    if(head==NULL)
    {
        temp->next=head;
        head=temp;
    }
    else
    {
        node*ptr=new node;
        ptr=head;
        while(ptr->next!=head)
        {
            ptr=ptr->next;
        }
        ptr->next=temp;
        temp->next=head;
    }
}
void printf()
{
    node*temp=new node;
    temp=head;
    do
    {
        cout<<temp->data<<" ";
        temp=temp->next;
    }while(temp!=head);

    cout<<endl;
}

int main()
{
    while(1)
    {
        cout<<"1-insert at begin"<<endl<<"2-insert at end"<<endl<<"3-exit"<<endl;
        int n;
        cout<<"enter your choice:"<<endl;
        cin>>n;
        cout<<"enter thee value you want to insert:"<<endl;
        int val;
        cin>>val;
        switch(n)
        {
        case 1:
            {
                cout<<"enter thee value you want to insert:"<<endl;
                  int val;
                  cin>>val;
                insert_begin(val);
                printf();
                break;
            }
        case 2:
            {
                cout<<"enter thee value you want to insert:"<<endl;
                int val;
                cin>>val;
                insert_end(val);
                printf();
                break;
            }
        case 3:

            {
                exit(0);
            }
        default:
            {
                cout<<"invalid choice :"<<endl;
            }
        }
    }
    return 0;
}