57 lines
2.0 KiB
C++
57 lines
2.0 KiB
C++
/// @file
|
|
/// @brief Educational implementation of a tree data structure with value semantics
|
|
/// @note The implementation relies on the "minimal incomplete type support" incomplete type support for std::list
|
|
/// - https://en.cppreference.com/w/cpp/feature_test#cpp_lib_incomplete_container_elements
|
|
|
|
#pragma once
|
|
|
|
#include <cstddef> // std::size_t
|
|
#include <functional> // std::function
|
|
#include <list> // std::string
|
|
|
|
namespace iue::svg {
|
|
|
|
template <typename T>
|
|
concept Value = requires(const T& a, T& b) {
|
|
T(a); ///< copy constructor (std::copy_constructible)
|
|
b = a; ///< copy assignment (std::assignable_from)
|
|
};
|
|
|
|
/// @brief Generic tree (tree with a dynamic unbound number of child nodes)
|
|
template <Value Value> struct Tree {
|
|
|
|
/// @brief Node in the tree
|
|
struct Node {
|
|
Value value; ///< Stored value
|
|
std::list<Node> nodes; ///< List of child nodes
|
|
};
|
|
|
|
using ValueVisitor = std::function<void(const Value& value, std::size_t level)>;
|
|
using NodeVisitor = std::function<void(const Node& node, std::size_t level)>;
|
|
|
|
Node org; ///< Root node of the tree
|
|
|
|
/// @brief Constructs a tree
|
|
/// @param Value held by the root node of the tree
|
|
/// @note This constructor avoids that the value type needs to be default-constructible
|
|
Tree(const Value& value) : org{value} {}
|
|
|
|
/// @brief Visit all values in the nodes in preorder using two visitors for down and up path
|
|
static void preorder(Node& root, const ValueVisitor& down, const ValueVisitor& up, std::size_t level = 0) {
|
|
down(root.value, level);
|
|
for (auto& child : root.nodes)
|
|
preorder(child, down, up, level + 1);
|
|
up(root.value, level);
|
|
}
|
|
|
|
/// @brief Visit all nodes in preorder using two visitors for down and up path
|
|
static void preorder(Node& root, const NodeVisitor& down, const NodeVisitor& up, std::size_t level = 0) {
|
|
down(root, level);
|
|
for (auto& child : root.nodes)
|
|
preorder(child, down, up, level + 1);
|
|
up(root, level);
|
|
}
|
|
};
|
|
|
|
} // namespace iue::svg
|