Binary Tree creation & inorder show

#include<iostream>
using namespace std;
struct node
{
string data;
node *Lc,*RC;
};
class BT
{
public:
node *create();
void show(node*);
};
node* BT::create()
{
string x;
node *p;
cout<<"enter Book Name -1 if Book is not available\n";
cin>>x;
if(x=="-1")
return NULL;
else
{
p=new node;
p->data=x;
p->Lc=NULL;
p->RC=NULL;
cout<<"enter LC of : "<<x<<"\n";
p->Lc=create();
cout<<"enter RC of : "<<x<<"\n";
p->RC=create();
}
return p;

}
void BT::show(node *ptr)
{
if(ptr!=NULL)
{
show(ptr->Lc);
cout<<ptr->data<<"-->";
show(ptr->RC);
}
}
int main()
{
BT b1;
node *root;
root=NULL;
root=b1.create();
cout<<"\nInorder....\n";
b1.show(root);
cout<<"\n";
cout<<"\nPreporder....\n";
b1.preorder(root);
cout<<"\n";
cout<<"Postorder...\n";
b1.postorder(root);
return 0;
}