Traverse tree without recursion and using any data structure

I got this problem statement in one of my technical interviews. I didn't find solution to this problem on google. SO I attempted it myself . It was fun solving this problem and I enjoyed it. Here is solution.

#include
#include
#include
typedef struct node
{
  struct node* left;
  struct node* right;
  struct node* parent;
  int data;
}T;
T* head=NULL;
void add_node(int data)
{
  T* t = (T *)malloc(sizeof(T));
  t->left=NULL;t->right=NULL;t->parent=NULL;t->data=data;
  if (head==NULL) {
   head = t;
  } else {
   T* tmp = head;
   while (1) {
   if (data < tmp->data) {
     // should go on left side
     if (tmp->left==NULL) {
       t->parent=tmp;
       tmp->left = t;
       break;
     }
     tmp=tmp->left;
   } else {
     // should go on right side
     if (tmp->right==NULL) {
      t->parent = tmp;
      tmp->right = t;
      break;
     }
     tmp=tmp->right;
   }
   }
  }
}

void myt(T* root) {
  if (root==NULL) {
    return;
  }
 int left_back=0,right_back=0;

 while(1)
 {
   if (root->left==NULL && root->right==NULL) {
     // I am child node . print my data and move to my parent
     printf(" %d",root->data);
     if (root->parent==NULL) {
       // we are THE ROOT . done traverse
       return;
     }
     if (root==(root->parent)->left) {
       // I was left child of parent
       left_back=1; right_back=0;
     } else {
       // I was right child of parent
       right_back=1; left_back=0;
     }
     root=root->parent;
     continue;
   }

   if (left_back==1) {
     // we have come back from left child   . print data
     printf(" %d",root->data);
     if (root->right!=NULL) {
       root=root->right;  left_back=0;right_back=0;
       continue;
     } else {
       // we dont have right child  . we have to back track
       if (root->parent==NULL) {
  // we are THE ROOT. Done traverse
  return;
       }

       if(root==(root->parent)->left) {
   left_back=1;right_back=0;
       } else {
   left_back=0;right_back=1;
       }
       root=root->parent;
       continue;
     }
   }

   if (right_back==1) {
     // we have come back from right node. we have to back track
     if (root->parent==NULL) {
       // we are THE ROOT. Done traverse
       return;
     }
     if(root==(root->parent)->left) {
       left_back=1;right_back=0;
     } else {
       left_back=0;right_back=1;
     }
     root=root->parent;
     continue;
   }

   if(root->left!=NULL) {
      left_back=0;right_back=0;
      root=root->left;
      continue;
   } else {
    // left child is not present. print data and move to right
    printf(" %d",root->data);
    root=root->right;
    left_back=0;right_back=0;
   }

 }
}

void traverse(T* h) {
  if (h==NULL) {return;}
  traverse(h->left);
  printf(" %d",h->data);
  traverse(h->right);
}
void main()
{
  clrscr();
  printf("\n enter elements \n");
  int n;
  while(1) {
    scanf("%d",&n);
    if(n==0) {
      break;
    }
    add_node(n);
  }
  printf("\n Inorder : ");
  traverse(head);
  printf("\nMinorder : ");
  myt(head);
  getch();
}