The most elegant way to print a Binary Tree

class TreeNode {
public:
  int val;
  TreeNode *left;
  TreeNode *right;
  TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
void display(TreeNode* root, int col = 0) {
  if(root == 0)    
    return;
  display(root->right, col + 1);
  for(int i = 0; i < col; ++i)   
    std::cout<<"| ";
  cout<<"|"<<root->val<<std::endl;
  display(root->left, col + 1);
}
int main() {

  TreeNode *root = new TreeNode(0);
  root->left = new TreeNode(1);
  root->right = new TreeNode(2);
  root->left->left = new TreeNode(3);
  root->left->right = new TreeNode(4);
  root->right->left = new TreeNode(5);
  root->right->right = new TreeNode(6);
  root->right->right->right = new TreeNode(7);

  display(root);
  return 0;
}

The most elegant way to print a Binary Tree,布布扣,bubuko.com

The most elegant way to print a Binary Tree

原文：http://blog.csdn.net/taoqick/article/details/20903701