draw binary ascii in c

btree.c

#include <stdio.h>
// http://web.archive.org/web/20071224095835/http://www.openasthra.com/wp-content/uploads/2007/12/binary_trees1.c
typedef struct Tree Tree;

struct Tree
{
  Tree * left, * right;
  int element;
};

Tree *make_empty(Tree *t)
{
  if (t != NULL)
  {
    make_empty(t->left);
    make_empty(t->right);
    free(t);
  }

  return NULL;
}

Tree *find_min(Tree *t)
{
  if (t == NULL)
  {
    return NULL;
  }
  else if (t->left == NULL)
  {
    return t;
  }
  else
  {
    return find_min(t->left);
  }
}

Tree *find_max(Tree *t)
{
  if (t == NULL)
  {
    return NULL;
  }
  else if (t->right == NULL)
  {
    return t;
  }
  else
  {
    return find_max(t->right);
  }
}

Tree *find(int elem, Tree *t)
{
  if (t == NULL)
  {
    return NULL;
  }

  if (elem < t->element)
  {
    return find(elem, t->left);
  }
  else if (elem > t->element)
  {
    return find(elem, t->right);
  }
  else
  {
    return t;
  }
}

//Insert i into the tree t, duplicate will be discarded
//Return a pointer to the resulting tree.
Tree * insert(int value, Tree * t)
{
  Tree * new_node;

  if (t == NULL)
  {
    new_node = (Tree *) malloc (sizeof (Tree));
    if (new_node == NULL)
    {
      return t;
    }

    new_node->element = value;

    new_node->left = new_node->right = NULL;
    return new_node;
  }

  if (value < t->element)
  {
    t->left = insert(value, t->left);
  }
  else if (value > t->element)
  {
    t->right = insert(value, t->right);
  }
  else
  {
    //duplicate, ignore it
    return t;
  }
  return t;
}

Tree * delete(int value, Tree * t)
{
  //Deletes node from the tree
  // Return a pointer to the resulting tree
  Tree * x;
  Tree *tmp_cell;

  if (t==NULL) return NULL;

  if (value < t->element)
  {
    t->left = delete(value, t->left);
  }
  else if (value > t->element)
  {
    t->right = delete(value, t->right);
  }
  else if (t->left && t->right)
  {
    tmp_cell = find_min(t->right);
    t->element = tmp_cell->element;
    t->right = delete(t->element, t->right);
  }
  else
  {
    tmp_cell = t;
    if (t->left == NULL)
      t = t->right;
    else if (t->right == NULL)
      t = t->left;
    free(tmp_cell);
  }

  return t;
}


//printing tree in ascii

typedef struct asciinode_struct asciinode;

struct asciinode_struct
{
  asciinode * left, * right;

  //length of the edge from this node to its children
  int edge_length;

  int height;

  int lablen;

  //-1=I am left, 0=I am root, 1=right
  int parent_dir;

  //max supported unit32 in dec, 10 digits max
  char label[11];
};


#define MAX_HEIGHT 1000
int lprofile[MAX_HEIGHT];
int rprofile[MAX_HEIGHT];
#define INFINITY (1<<20)

//adjust gap between left and right nodes
int gap = 3;

//used for printing next node in the same level,
//this is the x coordinate of the next char printed
int print_next;

int MIN (int X, int Y)
{
  return ((X) < (Y)) ? (X) : (Y);
}

int MAX (int X, int Y)
{
  return ((X) > (Y)) ? (X) : (Y);
}

asciinode * build_ascii_tree_recursive(Tree * t)
{
  asciinode * node;

  if (t == NULL) return NULL;

  node = malloc(sizeof(asciinode));
  node->left = build_ascii_tree_recursive(t->left);
  node->right = build_ascii_tree_recursive(t->right);

  if (node->left != NULL)
  {
    node->left->parent_dir = -1;
  }

  if (node->right != NULL)
  {
    node->right->parent_dir = 1;
  }

  sprintf(node->label, "%d", t->element);
  node->lablen = strlen(node->label);

  return node;
}


//Copy the tree into the ascii node structre
asciinode * build_ascii_tree(Tree * t)
{
  asciinode *node;
  if (t == NULL) return NULL;
  node = build_ascii_tree_recursive(t);
  node->parent_dir = 0;
  return node;
}

//Free all the nodes of the given tree
void free_ascii_tree(asciinode *node)
{
  if (node == NULL) return;
  free_ascii_tree(node->left);
  free_ascii_tree(node->right);
  free(node);
}

//The following function fills in the lprofile array for the given tree.
//It assumes that the center of the label of the root of this tree
//is located at a position (x,y).  It assumes that the edge_length
//fields have been computed for this tree.
void compute_lprofile(asciinode *node, int x, int y)
{
  int i, isleft;
  if (node == NULL) return;
  isleft = (node->parent_dir == -1);
  lprofile[y] = MIN(lprofile[y], x-((node->lablen-isleft)/2));
  if (node->left != NULL)
  {
    for (i=1; i <= node->edge_length && y+i < MAX_HEIGHT; i++)
    {
      lprofile[y+i] = MIN(lprofile[y+i], x-i);
    }
  }
  compute_lprofile(node->left, x-node->edge_length-1, y+node->edge_length+1);
  compute_lprofile(node->right, x+node->edge_length+1, y+node->edge_length+1);
}

void compute_rprofile(asciinode *node, int x, int y)
{
  int i, notleft;
  if (node == NULL) return;
  notleft = (node->parent_dir != -1);
  rprofile[y] = MAX(rprofile[y], x+((node->lablen-notleft)/2));
  if (node->right != NULL)
  {
    for (i=1; i <= node->edge_length && y+i < MAX_HEIGHT; i++)
    {
      rprofile[y+i] = MAX(rprofile[y+i], x+i);
    }
  }
  compute_rprofile(node->left, x-node->edge_length-1, y+node->edge_length+1);
  compute_rprofile(node->right, x+node->edge_length+1, y+node->edge_length+1);
}

//This function fills in the edge_length and
//height fields of the specified tree
void compute_edge_lengths(asciinode *node)
{
  int h, hmin, i, delta;
  if (node == NULL) return;
  compute_edge_lengths(node->left);
  compute_edge_lengths(node->right);

  /* first fill in the edge_length of node */
  if (node->right == NULL && node->left == NULL)
  {
    node->edge_length = 0;
  }
  else
  {
    if (node->left != NULL)
    {
      for (i=0; i<node->left->height && i < MAX_HEIGHT; i++)
      {
        rprofile[i] = -INFINITY;
      }
      compute_rprofile(node->left, 0, 0);
      hmin = node->left->height;
    }
    else
    {
      hmin = 0;
    }
    if (node->right != NULL)
    {
      for (i=0; i<node->right->height && i < MAX_HEIGHT; i++)
      {
        lprofile[i] = INFINITY;
      }
      compute_lprofile(node->right, 0, 0);
      hmin = MIN(node->right->height, hmin);
    }
    else
    {
      hmin = 0;
    }
    delta = 4;
    for (i=0; i<hmin; i++)
    {
      delta = MAX(delta, gap + 1 + rprofile[i] - lprofile[i]);
    }

    //If the node has two children of height 1, then we allow the
    //two leaves to be within 1, instead of 2
    if (((node->left != NULL && node->left->height == 1) ||
        (node->right != NULL && node->right->height == 1))&&delta>4)
    {
      delta--;
    }

    node->edge_length = ((delta+1)/2) - 1;
  }

  //now fill in the height of node
  h = 1;
  if (node->left != NULL)
  {
    h = MAX(node->left->height + node->edge_length + 1, h);
  }
  if (node->right != NULL)
  {
    h = MAX(node->right->height + node->edge_length + 1, h);
  }
  node->height = h;
}

//This function prints the given level of the given tree, assuming
//that the node has the given x cordinate.
void print_level(asciinode *node, int x, int level)
{
  int i, isleft;
  if (node == NULL) return;
  isleft = (node->parent_dir == -1);
  if (level == 0)
  {
    for (i=0; i<(x-print_next-((node->lablen-isleft)/2)); i++)
    {
      printf(" ");
    }
    print_next += i;
    printf("%s", node->label);
    print_next += node->lablen;
  }
  else if (node->edge_length >= level)
  {
    if (node->left != NULL)
    {
      for (i=0; i<(x-print_next-(level)); i++)
      {
        printf(" ");
      }
      print_next += i;
      printf("/");
      print_next++;
    }
    if (node->right != NULL)
    {
      for (i=0; i<(x-print_next+(level)); i++)
      {
        printf(" ");
      }
      print_next += i;
      printf("\\");
      print_next++;
    }
  }
  else
  {
    print_level(node->left,
                x-node->edge_length-1,
                level-node->edge_length-1);
    print_level(node->right,
                x+node->edge_length+1,
                level-node->edge_length-1);
  }
}

//prints ascii tree for given Tree structure
void print_ascii_tree(Tree * t)
{
  asciinode *proot;
  int xmin, i;
  if (t == NULL) return;
  proot = build_ascii_tree(t);
  compute_edge_lengths(proot);
  for (i=0; i<proot->height && i < MAX_HEIGHT; i++)
  {
    lprofile[i] = INFINITY;
  }
  compute_lprofile(proot, 0, 0);
  xmin = 0;
  for (i = 0; i < proot->height && i < MAX_HEIGHT; i++)
  {
    xmin = MIN(xmin, lprofile[i]);
  }
  for (i = 0; i < proot->height; i++)
  {
    print_next = 0;
    print_level(proot, -xmin, i);
    printf("\n");
  }
  if (proot->height >= MAX_HEIGHT)
  {
    printf("(This tree is taller than %d, and may be drawn incorrectly.)\n", MAX_HEIGHT);
  }
  free_ascii_tree(proot);
}


//driver routine
void main()
{
  //A sample use of these functions.  Start with the empty tree
  //insert some stuff into it, and then delete it
  Tree * root;
  int i;
  root = NULL;

  make_empty(root);
  while (scanf("%d", &i) != EOF){
    root = insert(i, root);
  }
  print_ascii_tree(root);

  make_empty(root);
}