GeneralTree_to_BinaryTree

#include<iostream.h>
#include<conio.h>
#include<string.h>
typedef struct node
{
char data;
node *left;
node *right;
}bnode;
struct pnode
{int level;
bnode *loc;
};
class stack
{
int top;
pnode pred[10];
public:
stack();
void push(pnode p);
pnode peek();
void pop();
};
stack::stack()
{
top=-1;
}
void  stack::push(pnode p)
{
top++;
pred[top].level=p.level;
pred[top].loc=p.loc;
}
pnode stack::peek()
{
return pred[top];
}
void stack::pop()
{
top--;
}
class gtbt
{
bnode *head;
public:
gtbt();
void convert();
void preorder(bnode *t);
void inorder(bnode *t);
void postorder(bnode *t);
void t();
};
gtbt::gtbt()
{
head=new bnode;
head->left=NULL;
head->right=head;
}
void gtbt::convert()
{
stack s;
pnode p;
int lev;
char name;
bnode *temp;
p.level=0;
p.loc=head;
s.push(p);
clrscr();
cout<<"0 to exit";
while(1)
{
cout<<"\nenter level and name:";
cin>>lev;
if(lev==0)break;
cin>>name;
temp=new bnode;
temp->data=name;
temp->left=NULL;
temp->right=NULL;
p=s.peek();
if(lev>p.level)
{
p.loc->left=temp;
}
else
{
while(p.level>lev)
{
s.pop();
p=s.peek();
}
if(p.level<lev)
{
cout<<"error";
return;
}
p.loc->right=temp;
s.pop();
}
p.level=lev;
p.loc=temp;
s.push(p);
}
}
void gtbt::t()
{
cout<<"\npreorder"<<endl;
preorder(head->left);
cout<<"\ninorder"<<endl;
inorder(head->left);
cout<<"\npostorder"<<endl;
postorder(head->left);
}
void gtbt::preorder(bnode *t)
{
if(t!=NULL)
{
cout<<t->data<<" ";
preorder(t->left);
preorder(t->right);
}
}
void gtbt::inorder(bnode *t)
{
if(t!=NULL)
{
inorder(t->left);
cout<<t->data<<" ";
inorder(t->right);
}
}
void gtbt::postorder(bnode *t)
{
if(t!=NULL)
{
postorder(t->left);
postorder(t->right);
cout<<t->data<<" ";
}
}
void main()
{
gtbt gb;
gb.convert();
gb.t();
getch();
}