C语言实现Huffman编码

#include<stdio.h>
#include<malloc.h>
#include<string.h>
#include<stdlib.h>
typedef struct
{
         int weight;
         char ch;
         int parent,lchild,rchild;
}HTNode,*HuffmanTree;
typedef struct
{
char ch;
char *chs;
}HuffmanCode;
typedef struct
{
char ch;
int weight;
}sw;
typedef struct
{
HuffmanTree HT;
HuffmanCode *HC;
}huf;
void select(HTNode * HT,int n,int *n1,int *n2)
{
         int i=1;         int n3;
         while(HT[i].parent!=0)
         i++;

         *n1=i;
          i++;
         while(HT[i].parent!=0)         i++;
         *n2=i;
         if(HT[*n1].weight<HT[*n2].weight)
         {         n3=*n1;*n1=*n2;*n2=n3;}
         for(i++;i<=n;i++)
         {
           if(HT[i].parent==0)
           {         if(HT[i].weight<HT[*n1].weight)
         *n1=i;
              else if(HT[i].weight<HT[*n2].weight)
         *n2=i;
           }
         }
}
huf * HuffmanCoding(HuffmanTree HT,HuffmanCode *HC,sw *w,int n,huf *HUF)
{int m,i,s1,s2,start,c,f;
HuffmanTree p;
char *cd;
if(n<=1) return 0;
m=2*n-1;
HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));
for(p=HT+1,i=1;i<=n;i++,p++,w++)
{p->weight=w->weight;p->ch=w->ch;p->parent=0;p->lchild=0;p->rchild=0;}
for(;i<=m;i++,p++)
{p->weight=0;p->ch='^';p->parent=0;p->lchild=0;p->rchild=0;}
for(i=n+1;i<=m;i++)
{
           select(HT,i-1,&s1,&s2);