这是树的应用——哈夫曼编码，从键盘输入若干字符及每个字符出现的频率，将字符出现的频率作为结点的权值，建立哈夫曼树，然后对各个字符进行哈夫曼编码-This is the application of tree- Huffman coding, a number of characters from the keyboard input and the frequency of each character, the character frequency as node weights set up Huffman tree, then on the various characters Hough Cayman coding