构建哈夫曼树(可构造哈夫曼编码)

#include<stdio.h>
#include<malloc.h>
#include<string.h>
typedef struct
{
   unsigned int weight;
   unsigned int parent,lchild,rchild;
}HTNode,*HuffmanTree; 

typedef char **HuffmanCode;

void Select(HuffmanTree &HT,int n,int &s1,int &s2)
{  
int i;
    s1=-1;s2=-1;
    for (i=1;i<=n;i++) 
{
      if (HT[i].parent==0)
if (s1==-1)
s1=i;
else 
  if (s2==-1)
if (HT[i].weight<HT[s1].weight)
{
s2=s1;
s1=i;
}
else
s2=i;
  else