三只小猪盖房子话剧:请高手帮我看看这个程序的问题!

我写的这个程序可以运行,但是就是有错误,请高手帮我改一下,谢谢!
#include "stdafx.h"
#include<iostream.h>
#include<stdlib.h>
typedef struct {
int weight;
int parent,lchild,rchild;
}HTNode,*HuffmanTree;
typedef char **HuffmanCode;
void select(HuffmanTree &HT,int n,int s1,int s2)
{
int i;
for(i=1;i<=n;i++)
if(s1>HT[i].weight&&HT[i].parent==0) s1=i;
for(i=1;i<=n;i++)
if(s1>HT[i].weight&&HT[i].parent==0&&i!=s1) s2=i;
}
void strcpy(char *a,char *b)
{
while((*a++=*b++)!=0);
}

void HuffmanCoding(HuffmanTree &HT,HuffmanCode &HC,int *w,int n) {
int s1,s2,start,i,c,f,m;
char *cd;
m=2*n-1;
s1=255;
s2=255;
HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));
for(i=1;i<=n;++i,++w)
{
HT[i].weight=*w;
HT[i].parent=HT[i].lchild=HT[i].rchild=0;
}
for(;i<=m;i++)
{
HT[i].weight=0;
HT[i].parent=HT[i].lchild=HT[i].rchild=0;
}
for(i=n+1;i<=m;i++)
{
select(HT,i-1,s1,s2);
HT[s1].parent=i;
HT[s2].parent=i;
HT[i].lchild=s1;
HT[i].rchild=s2;
HT[i].weight=HT[s1].weight+HT[s2].weight;
}

HC=(HuffmanCode)malloc((n+1)*sizeof(char *));
cd=(char *)malloc(n*sizeof(char));
cd[n-1]='\0';
for(i=1;i<=n;++i) {
start=n-1;
for(c=i,f=HT[i].parent;f!=0;c=f,f=HT[f].parent)
{
if(HT[f].lchild==c) cd[--start]='0';
else cd[--start]='1';
}
HC[i]=(char *)malloc((n-start)*sizeof(char));
strcpy(HC[i],&cd[start]);
}

}

void main() {
int a[100];
int i,n;
HuffmanTree HT;
HuffmanCode HC;
cout<<"请输入结点个数:";
cin>>n;
for(i=0;i<n;i++) {
cout<<"请输入第"<<i+1<<"个结点的权值：";
cin>>a[i];
}
HuffmanCoding(HT,HC,a,n);
for(i=0;i<n;i++)
cout<<HC[i]<<endl;
}