0001 HuffTree* minHChar ( HuffForest* forest ) { //在Huffman森林中找出权重最小的超字符
0002    ListNodePosi<HuffTree*> m = forest->first(); //从首节点出发，遍历所有节点
0003    for ( ListNodePosi<HuffTree*> p = m->succ; forest->valid( p ); p = p->succ )
0004       if ( m->data->root()->data.weight > p->data->root()->data.weight ) //不断更新
0005          m = p; //找到最小节点（所对应的Huffman子树）
0006    return forest->remove( m ); //从森林中取出该子树，并返回
0007 }
0008 
0009 HuffTree* generateTree ( HuffForest* forest ) { //Huffman编码算法
0010    while ( 1 < forest->size() ) {
0011       HuffTree* T1 = minHChar ( forest ); HuffTree* T2 = minHChar ( forest );
0012       HuffTree* S = new HuffTree();
0013       S->insert ( HuffChar ( '^', T1->root()->data.weight + T2->root()->data.weight ) );
0014       S->attach ( T1, S->root() ); S->attach ( S->root(), T2 );
0015       forest->insertAsLast ( S );
0016    } //assert: 循环结束时，森林中唯一（列表首节点中）的那棵树即Huffman编码树
0017    return forest->first()->data;
0018 }