Non Recursive algorithms for inorder,preorder and postorder traversals(Binary tree Traversals)

Binary Tree Traversals (Non Recursive)

preorder(Node temp)

{

     Node ptr;

     ptr=temp;

     while(ptr!=NULL||top!=-1)

     {

                     if(ptr!=NULL)

                     {

                                  Print ptr->data

                                  push(ptr);

                                  ptr=ptr->lchild

                     }

                     else

                     {

                         ptr=pop();

                         ptr=ptr->rchild;

                     }

     }

}

inorder(Node temp)

{

     Node ptr;

     ptr=root;

     while(ptr!=NULL||top!=-1)

     {

                     if(ptr!=NULL)

                     {

                                  push(ptr);

                                  ptr=ptr->lchild;

                     }

                     else

                     {

                         ptr=pop();

                         print ptr->data;

                         ptr=ptr->rchild;

                     }

     }

}

postorder(Node temp)

{

     Node ptr;

     ptr=root;

     do

     {

      while(ptr!=NULL)

      {

            push(ptr->rchild);

            push(ptr);

            ptr=ptr->lchild;

           

      }

      ptr=pop();

      if((ptr->rchild!=NULL)&&(ptr->rchild==info[top]))

      {

         pop();

         push(ptr);

         ptr=ptr->rchild;

      }              

      else

      {

         Print ptr->data

         ptr=NULL;

      }

     }while(top!=-1);

}