我们来看看哈夫曼的类型定义：

typedef struct{
unsigned int weight;
unsigned int parent, lchild, rchild;
}HTNode, *HuffmanTree;
/*存放哈夫曼编码*/
typedef char **HuffmanCode;

void HuffmanCoding (HuffmanTree *HT,HuffmanCode *HC,int *w,int n)
{
 /*构造哈夫曼树HT,哈夫曼树的代码存放在HC中，w为n个字符的权值*/
 int m, i, s1, s2, start;
 unsigned int c, f;
 HuffmanTree p;
 char *cd;
 if(n<=1)
 {
  return ;
 }
 m=2*n-1;
 *HT=(HuffmanTree)malloc((m+1)*sizeof(HTCode));/*第零个存储单元不用*/
 for(p=*HT+1; i=1; i<=n; i++, p++)
 {
  ///初始化n个叶子结点
  (*p).weight=*w;
  (*p).parent=0;
  (*p).lchild=0;
  (*p).rchild=0;
 }
 for(; i<=m; i++)
 {
  ///初始化n-1个非叶子结点
  (*p).parent=0;
 }
 for(i=n+1; i<=m; i++)       //构造哈夫曼树
 {
  Select(HT, i-1; &s1, &s2);  ///查找树中权值最小的两个结点
  (*HT)[s1].parent=(*HT)[s2].parent=i;
  (*HT)[i].lchild=s1;
  (*HT)[i].rchild=s2;
  (*HT)[i].weight=(*HT)[s1].weight+(*HT)[s2].weight;
 }
 /*从叶子结点到根结点求每个字符的哈夫曼编码*/
 *HC=（HuffmanCode)malloc((n+1)*sizeof(char *))
 
 cd=(char *)malloc(n*sizeof(char));
 cd[n-1]='\0';
 /*求n个叶子的哈夫曼编码*/
 for(int i=1; i<=n; i++)
 {
  start=n-1;
  for(int c=i, f=(*HT)[i],parent; f!=0; c=f, f=(*HT)[f].parent)
  {
   /*从叶子结点到根结点求编码*/
   if((*HT)[f].lchild==c)
   {
    cd[--start]='0';
   }
   else
   {
    cd[--start]='1';
   }
  }
  (*HC)[i]=(char*)malloc((n-start)*sizeof(char));
 }
 free(cd)
}

void Min(HussmanTree t; int n)
{
 int i,flag;
 int f=infnity;///f为无限大
 for(int i=1; i<=n; i++)
 {
  if(t[i].weight<f && t[i].parent==0)
  {
   f=t[i].weight;
   flag=i;
  }
 }
 t[falg].parent=i;
 return falg;
}

void Select(HuffmanTree *t, int n, int *s1, int *s2)
{
 int x;
 *s1=Min(*t,n);
 *s2=Min(*t,n);
 if((*t)[*s1].weight>(*t)[*s2].weight)
 {
  x=*s1;
  *s1=*s2;
  *s2=x;
 }
}