构建哈夫曼树并打印哈夫曼编码

#include <stdio.h>
#include <stdlib.h>

typedef struct _Node{
	float data;
	struct _Node *lchild;
	struct _Node *rchild;
	int huffmanCode[10],pos;//保存编码,在数组中从后往前存储，最多10位
} Node,*Tree;
/* 排序算法,从大到小 */
void Sort(float a[],int low,int high)
{
	int i;
	float temp;
	if(low == high)return;

	for(i=low; i<=high; i++){
		if(a[i] > a[low]){
			temp = a[low];
			a[low] = a[i];
			a[i] = temp;
		}
	}
	Sort(a,low+1,high);
}
/* 将一个字符型数组 char a[]转化为 Tree型数组，而且已经从大到小排序
 * 为构建哈夫曼树做准备*/
Tree* InitHuffmanTree(float a[],int count)
{
    int i,j;
    Tree T ;
	Sort(a,0,count-1);//先排序
    Tree *HuffmanTrees = (Tree *)malloc(sizeof(Tree));

    for(i=0; i<count; i++){
        T = (Node *)malloc(sizeof(Node));
        T->data = a[i];
        T->lchild = T->rchild = NULL;
		T->pos = 10;

        HuffmanTrees[i] = T;
    }
    return HuffmanTrees;
}
/* 给一棵子树的节点赋哈夫曼编码 */
void Encoding(Tree head,int code)
{
	if(!head)return;

	head->huffmanCode[--(head->pos)] = code;
	Encoding(head->lchild,code);
	Encoding(head->rchild,code);
}
/* 构建哈夫曼树，打印哈夫曼编码
 * huffmanTrees[]中存储的是所有huffman树的根，
 * 而且已经从大到小排序*/
Tree CreateHuffmanTree(Tree *huffmanTrees,int count)
{
    int i;

    if(count <= 1)return huffmanTrees[0];

    Node *newTree = NULL;
    if(!(newTree=(Node *)malloc(sizeof(Node))))printf("overflow!\n");
	
    newTree->data   = huffmanTrees[count-1]->data + huffmanTrees[count-2]->data;
    newTree->lchild = huffmanTrees[count-1];
	Encoding(huffmanTrees[count-1],0);//修改子树的哈夫曼编码
    newTree->rchild = huffmanTrees[count-2];
	Encoding(huffmanTrees[count-2],1);
	newTree->pos = 10;
	
    count -= 2;
    /*插入合适位置（从大到小顺序）*/
    for(i=count; i>0 && newTree->data > huffmanTrees[i-1]->data; i--)
    {
		huffmanTrees[i] = huffmanTrees[i-1];
    }
    huffmanTrees[i] = newTree;
    count++;

    return CreateHuffmanTree(huffmanTrees,count);
}
/* 输出哈夫曼编码 : 左0右1*/
float printHuffmanCode(Tree head)
{
	int i;
	static float length = 0,TotLen=0,num=0;
	if(!head)return length;
	if (!head->lchild && !head->rchild)
	{
		for(i=head->pos; i<10; i++)printf("%d",head->huffmanCode[i]);
		printf("\t%.2f\n",head->data);
		TotLen += head->data * (10-head->pos);
		num += head->data;
	}
	printHuffmanCode(head->lchild);
	printHuffmanCode(head->rchild);

	length = TotLen/num;
	return length;

}

int main(int argc, char *argv[])
{
	float a[] = {.23,.11,.05,.03,.29,.14,.07,.08},length;
	int count = 8;

    Tree *huffmanTrees = InitHuffmanTree(a,count);
    Tree huffmanTree = CreateHuffmanTree(huffmanTrees,count);

	printf("Here is the HuffmanCode :\n\n");
    length = printHuffmanCode(huffmanTree);
	printf("\nAverage length of the code : %.2f\n",length);
	getchar();
}