Seed7

$ include "seed7_05.s7i";

type: tree_type is record
  left: ptr tree_type;
  right: ptr tree_type;
  key: integer;
  info: string;
end record;

const func: insert_node (ref var tree: ptr tree_type, in key: integer,
    in info: string) is func
  result
    var tree: ptr tree_type;
  begin
    if tree = NULL then
      tree := new tree_type;
      tree->key := key;
      tree->info := info;
      tree->left := NULL;
      tree->right := NULL;
    elsif key < tree->key then
      insert_node(tree->left, key, info);
    elsif key > tree->key then
      insert_node(tree->right, key, info);
    else
      tree->info := info;
    end if;
  end func;

const proc: print_tree (in tree: ptr tree_type) is func
  begin
    if tree <> NULL then
      print_tree(tree->left);
      writeln(tree->key <& ": " <& tree->info);
      print_tree(tree->right);
    end if;
  end func;