binarytree.h

游戏开发数据结构-Data.Structures.for.Game.Programmers

// ============================================================================
// Data Structures For Game Programmers
// Ron Penton
// BinaryTree.h
// This is the Binary Tree class
// ============================================================================
#ifndef BINARYTREE_H
#define BINARYTREE_H


// -------------------------------------------------------
// Name:        BinaryTree
// -------------------------------------------------------
template<class DataType>
class BinaryTree
{
public:
    // typedef the tree class into "Node" to make it 
    // easier to work with.
    typedef BinaryTree<DataType> Node;

// ----------------------------------------------------------------
//  Name:           m_data
//  Description:    This is the data in the node
// ----------------------------------------------------------------
    DataType m_data;

// ----------------------------------------------------------------
//  Name:           m_parent
//  Description:    This is a pointer to the parent node.
//                  If 0, then it is the parent node.
// ----------------------------------------------------------------
    Node* m_parent;

// ----------------------------------------------------------------
//  Name:           m_left, m_right
//  Description:    These are the children of the node.
// ----------------------------------------------------------------
    Node* m_left;
    Node* m_right;


// ----------------------------------------------------------------
//  Name:           BinaryTree
//  Description:    Constructor; creates an empty node
//  Arguments:      None.
//  Return Value:   None.
// ----------------------------------------------------------------
    BinaryTree()
    {
        m_parent = 0;
        m_left = 0;
        m_right = 0;
    }


// ----------------------------------------------------------------
//  Name:           BinaryTree
//  Description:    Data Constructor; creates a node with data
//  Arguments:      p_data - the data to store in the node
//  Return Value:   None.
// ----------------------------------------------------------------
    BinaryTree( DataType p_data )
    {
        m_parent = 0;
        m_left = 0;
        m_right = 0;
        m_data = p_data;
    }

// ----------------------------------------------------------------
//  Name:           ~BinaryTree
//  Description:    Destructor; recursively destroys the tree.
//  Arguments:      None.
//  Return Value:   None.
// ----------------------------------------------------------------
    ~BinaryTree()
    {
        Destroy();
    }

// ----------------------------------------------------------------
//  Name:           Destroy
//  Description:    This deletes the left and right children.
//  Arguments:      None.
//  Return Value:   None.
// ----------------------------------------------------------------
    void Destroy()
    {
        // if the left child exists, delete it.
        if( m_left )
            delete m_left;
        m_left = 0;

        // if the right child exists, delete it.
        if( m_right )
            delete m_right;
        m_right = 0;
    }


// ----------------------------------------------------------------
//  Name:           Count
//  Description:    Constructor; creates an empty node
//  Arguments:      None.
//  Return Value:   The number of nodes in the tree
// ----------------------------------------------------------------
    int Count()
    {
        // the count is set to 1, counting this node.
        int c = 1;

        // recursively add the counts of each child.
        if( m_left )
            c += m_left->Count();
        if( m_right )
            c += m_right->Count();

        // return the count.
        return c;
    }

};



// ----------------------------------------------------------------
//  Name:           Preorder
//  Description:    performs a preorder traversal on a tree
//  Arguments:      p_node - the node to start processing at.
//                  p_process - a function pointer to the process
//                              function
//  Return Value:   None.
// ----------------------------------------------------------------
template <class DataType>
void Preorder( BinaryTree<DataType>* p_node, 
               void (*p_process)(BinaryTree<DataType>*) )
{
    // if the node exists
    if( p_node )
    {
        // process the current node
        p_process( p_node );

        // process the left child
        if( p_node->m_left )
            Preorder( p_node->m_left );

        // process the right node
        if( p_node->m_right )
            Preorder( p_node->m_right );
    }
}


// ----------------------------------------------------------------
//  Name:           Inorder
//  Description:    performs an inorder traversal on a tree
//  Arguments:      p_node - the node to start processing at.
//                  p_process - a function pointer to the process
//                              function
//  Return Value:   None.
// ----------------------------------------------------------------
template <class DataType>
void Inorder( BinaryTree<DataType>* p_node, 
              void (*p_process)(BinaryTree<DataType>*) )
{
    // if the node exists
    if( p_node )
    {
        // process the left node
        if( p_node->m_left )
            Preorder( p_node->m_left );

        // process the current node
        p_process( p_node );

        // process the right node
        if( p_node->m_right )
            Preorder( p_node->m_right );
    }
}


// ----------------------------------------------------------------
//  Name:           Postorder
//  Description:    performs a postorder traversal on a tree
//  Arguments:      p_node - the node to start processing at.
//                  p_process - a function pointer to the process
//                              function
//  Return Value:   None.
// ----------------------------------------------------------------
template <class DataType>
void Postorder( BinaryTree<DataType>* p_node, 
                void (*p_process)(BinaryTree<DataType>*) )
{
    // if the node exists
    if( p_node )
    {
        // process the left node
        if( p_node->m_left )
            Preorder( p_node->m_left );

        // process the right node
        if( p_node->m_right )
            Preorder( p_node->m_right );

        // process the current node
        p_process( p_node );
    }
}



// ----------------------------------------------------------------
//  Name:           GetDepth
//  Description:    Recursively calculates the depth of a tree.
//  Arguments:      p_node - the root of the tree
//  Return Value:   The depth; 0 is the lowest.
// ----------------------------------------------------------------
template<class DataType>
int GetDepth( BinaryTree<DataType>* p_tree )
{
    // start off with -1 for the depth of each child
    int left = -1;
    int right = -1;

    // calculate the depth of the left child
    if( p_tree->m_left != 0 )
        left = GetDepth( p_tree->m_left );

    // calculate the depth of the right child
    if( p_tree->m_right != 0 )
        right = GetDepth( p_tree->m_right );

    // take the larger of the two depths, add one, and return.
    return ( left > right ? left : right ) + 1;
}

#endif