Binary Tree Traversal

#include<iostream.h>

#include<conio.h>

class tree

 {

public:

 char info;

 tree *lchild;

 tree *rchild;

 };

class treetraversal

 {

private:

  char x;

public:

  void input(tree *p);

  void preorder(tree *p);

  void inorder(tree *p);

  void postorder(tree *p);

 };

void treetraversal::input(tree *ptr)

 {

cout<<"\n\tEnter the element:";

cin>>x;

if(x=='0')

          ptr->info='$';

else

      {

ptr->info=x;

cout<<"\n\t"<<ptr->info<<"Left is:\n"<<endl;

ptr->lchild=new tree;

input(ptr->lchild);

cout<<"\n\t"<<ptr->info<<"Right is :\n"<<endl;

ptr->rchild=new tree;

input(ptr->rchild);

}

 }

void treetraversal::preorder(tree *ptr)

 {

if(ptr->info!='$')

 {

cout<<ptr->info;

preorder(ptr->lchild);

preorder(ptr->rchild);

 }

 }

void treetraversal::inorder(tree *ptr)

 {

if(ptr->info!='$')

      {

           inorder(ptr->lchild);

 cout<<ptr->info;

 inorder(ptr->rchild);

 }

  }

 void treetraversal::postorder(tree *ptr)

  {

 if(ptr->info!='$')

  {

           postorder(ptr->lchild);

           postorder(ptr->rchild);

cout<<ptr->info;

  }

  }

 void main()

  {

 treetraversal t;

      tree *te=new tree;

      clrscr();

 t.input(te);

 cout<<"\n\tThe Pre-order traversal for the given tree is:";

 t.preorder(te);

      cout<<"\n\tThe In-order traversal for the given tree is:";

 t.inorder(te);

      cout<<"\n\tThe Post-order traversal for the given tree is:";

      t.postorder(te);

 getch();

  }