哈夫曼树的一些操作

//      哈夫曼树
//    完成以下功能。
//     1.初始化模块.从键盘输入N个字符及N个权值，建立哈夫曼树。
//     2.编码功能.利用建立的哈夫曼树，对一段正文进行编码，然后将其保存起来。
//     3.译码系统。
//     4.打印功能。
//        数据描述 :用顺序储存结构表示哈夫曼数的结点结构定义。
//typedef struct
//{   unsigned int weight;
//    unsigned int parent,lchild,rchild;
//}HTDode,*HuffmanTree;
                   
#include"stdio.h"
#include"string.h"
#include"stdlib.h"
#include"malloc.h"
#include"conio.h"
////////////   定义结构成员
typedef  struct {
  unsigned int weight;
  unsigned int parent;
  unsigned int lchild;
  unsigned int rchild;
}HTNode,*HuffmanTree;
typedef char **HuffmanCode;
typedef  struct {
 unsigned int s1;
    unsigned int s2;
}MinCode;
void Error(char *message);
HuffmanCode HuffmanCoding(HuffmanTree HT,HuffmanCode HC,unsigned int *w,unsigned int n);
MinCode   Select(HuffmanTree HT,unsigned int n);
void Error(char *message)
{     fprintf(stderr,"Error:%s\n",message);  exit(1);}
///////////////////////////////////////////           ///////////////////////////
HuffmanCode HuffmanCoding(HuffmanTree HT,HuffmanCode HC,unsigned int *w,unsigned int n)
{    unsigned int i,s1=0,s2=0;
     HuffmanTree p;
     char *cd;
     unsigned int f,c,start,m;
     MinCode min;
     if(n<=1) Error("Code too small!");
     m=2*n-1;
     HT=(HuffmanTree)(malloc)((m+1)*sizeof(HTNode));
     for(p=HT,i=0;i<=n;i++,p++,w++)
  {   p->weight=*w;  p->parent=0;  p->lchild=0; p->rchild=0;}
        for(;i<=m;i++,p++)
  { p->weight=0;  p->parent=0;  p->lchild=0; p->rchild=0;}
          for(i=n+1;i<=m;i++)
    { min=Select(HT,i-1);
            s1=min.s1 ; s2=min.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;
    }
       printf("HT  List:\n");
       printf("Number\t\tweight\t\tparent\t\tlchild\t\trchild\n");
       for(i=1;i<=m;i++)
    printf("%d\t\t%d\t\t%d\t\t%d\t\t%d\n",i,HT[i].parent,HT[i].lchild,HT[i].rchild);
       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]);

 }
  free(cd);
  return HC;
}   
//////////// /////////////////////////////
MinCode Select(HuffmanTree   HT,unsigned int n)
{  unsigned int min,secmin;
   unsigned int temp;
   unsigned int i,s1,s2,tempi;
   MinCode  code ; s1=1 ;s2=1;
   for(i=1;i<=n;i++)
      if(HT[i].parent==0)
   { min=HT[i].weight;s1=i;break;}
     tempi=i++;
   for(;i<=n;i++)
    if(HT[i].weight<min&&HT[i].parent==0)
    {min=HT[i].weight;s1=i;
    }
      for(i=tempi;i<=n;i++)
    if(HT[i].parent==0&&i!=s1)
    {secmin=HT[i].weight;s2=i;break;
    }
   for(i=1;i<=n;i++)
    if(HT[i].weight,secmin&&i!=s1&&HT[i].parent==0)
    {secmin=HT[i].weight; s2=i ;
    }
   if(s1>s2)
   { tempi=s1;s1=s2;s2=tempi;}
     code.s1=s1;code.s2=s2;
  return code;
}
///////////////       主函数    //////////////////////
void main()
{   HuffmanTree HT=NULL;
    HuffmanCode HC=NULL;
    unsigned int *w=NULL;
    unsigned int i,n;
    printf("Input  n:\n");
    scanf("%d",&n);
    w=(unsigned int *)malloc((n+1)*sizeof(unsigned int *));
   w[0]=0;
    printf("Enter weight:\n");
    for(i=1;i<=n;i++)
 {  printf("w[%d]=",i);  scanf("%d",&w[i]);
 }
   HC=HuffmanCoding(HT,HC,w,n);
   printf("HuffmanCode:\n");
    printf("Number\t\tWeight\t\tCode\n");
   for(i=1;i<=n;i++)
   printf("%d\t\t%d\t\t%s\n",i,w[i],HC[i]);
}