Singly Linked List in (C++)

#include<iostream>
using namespace std;
struct Node
{
    int data;
    Node *next;
    Node *prev;
};
Node *Head=NULL;
Node *Tail=NULL;
Node *createNewNode(int value)
{
    Node *newNode=new Node;
    newNode->data=value;
    newNode->next=NULL;
    newNode->prev=NULL;
    return newNode;
}
int getValue()
{
    int x;
    cout<<"Enter Input:";
    cin>>x;
    return x;
}

void createList(int total)
{
    Node *currNode=Head=Tail=createNewNode(getValue());
    for(int i=1;i<total;i++)
    {
        Node *newNode=createNewNode(getValue());
        currNode->next = newNode;
        newNode->prev = currNode;
        Tail = newNode;
        currNode=currNode->next;
    }

}
void show()
{
    Node *currNode=Head;
    while(currNode!=NULL)
    {
        cout<<currNode->data<< "   ";
        currNode=currNode->next;
    }
}
void reverse_show()
{
    Node *currNode=Tail;
    while(currNode!=NULL)
    {
        cout<<currNode->data<< "   ";
        currNode=currNode->prev;
    }
}
void insertfirst(int v)
{
    Node *currNode=createNewNode(v);
    currNode->next=Head;
    Head=currNode;
}
void insertLast(int v)
{
    Node *currNode=Head;
    while(currNode->next!=NULL)
    {
        currNode=currNode->next;
    }
    Node *newNode=createNewNode(v);
    currNode->next=newNode;

}
void insertAnyPosition(int position,int v)
{
    Node *currNode=Head;
    for(int i=1;i<position;i++)
    {
        currNode=currNode->next;
    }
    Node *newNode=createNewNode(v);
    newNode->next=currNode->next;
    currNode->next=newNode;
}
void delete_First()
{
    Node *currNode=Head;
    Head=currNode->next;
    delete currNode;
}
void delete_Last()
{
    Node *currNode=Head;
    while(currNode->next->next!=NULL)
    {
        currNode=currNode->next;
    }
    Node *myNode=currNode->next;
    delete myNode;
    currNode->next=NULL;
}
void deleteAnyposition(int position)
{
    Node *currNode=Head;
    for(int i=1;i<position;i++)
    {
        currNode=currNode->next;
    }
    Node *newNode=currNode->next;
    currNode->next=currNode->next->next;
    delete newNode;
}

int main()
{
    createList(4);
    cout<<"The create List:"<<endl;
    show();
    cout<<"\nInsert First:"<<endl;
    insertfirst(0);
    show();
    cout<<"\nInsert any position:"<<endl;
    insertAnyPosition(2,11);
    show();
    cout<<"\nInsert Last:"<<endl;
    insertLast(6);
    show();
    cout<<"\nDelete from First:"<<endl;
    delete_First();
    show();
    cout<<"\nDelete from Any position:"<<endl;
    deleteAnyposition(2);  //2 is position
    show();
    cout<<"\nDelete from Last:"<<endl;
    delete_Last();
    show();
    return 0;
}