这是一个求哈夫曼树和哈夫曼编码的程序：1.count函数统输入字符串的频数2.构建哈夫曼树3.求哈夫曼编码。但是求哈夫曼编码是，那个子函数出问题了，程序运行到那个函数时终止了，求各位大牛指导，代码如下：
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MaxSize 52

struct TreeNode
{
    char ch;
    int weight;
    int parent;
    int lchild;
    int rchild;
};
typedef struct TreeNode HFTreeNode;
typedef HFTreeNode HuffmanTree;

struct CodeNode
{
    char ch;
    char bits[6];
};
typedef struct CodeNode CodeNode;
typedef CodeNode HuffmanCode[6];
void Count()
{
    char ch;char a[52]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n',
    'o','p','q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G',
    'H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
    int count[52]={0};int i; int j;
    for(j=0;j<52;j++)
       count[j]=0;
    printf("请输入一段英文字符:\n");
    ch=getchar();
    for(i=0;(i<100)&&(ch!='\n');i++)
    {
        for(j=0;j<52;j++)
        {
            if(ch==a[j])
            count[j]++;
        }
        ch=getchar();
    }
   
    printf("出现的字符和次数如下：\n");
    for(j=0;j<52;j++)
    {
        if(count[j]!=0)
        {
            printf("%c",a[j]);
            printf("    %d\n",count[j]);
        }
    }     
}
void SelectMin(HuffmanTree *HT,int g,int &s1,int &s2);
void CreateHuffmanTree(HuffmanTree *T,int n)
{
    int i,m,w,p1,p2;
    char a;
    if(n<1)
    {
        printf("不能构建哈弗曼树！");
        exit(1);
    }
    m=2*n;
    for(i=1;i<m;i++)
    {
        T[i].parent=0;
        T[i].lchild=0;
        T[i].rchild=0;
        T[i].weight=0;
         }
         
    printf("请输入叶子节点的权值：\n");     
    for(i=1;i<=n;i++)
    {
        scanf("%d",&w);
        T[i].weight=w;
        printf("   %d\n",w);
    }
   
    for(i=n+1;i<=m-1;i++)
    {
        SelectMin(T,i-1,p1,p2);
        T[p1].parent=T[p2].parent=i;
        T[i].lchild=p1;
        T[i].rchild=p2;
        T[i].weight=T[p1].weight+T[p2].weight;
    }
   
    for(i=1;i<=m-1;i++)
    {
        printf("%d",T[i].weight);
        printf("  %d",T[i].parent);
        printf("  %d",T[i].lchild);
        printf("  %d\n",T[i].rchild);
    }     
}
void SelectMin(HuffmanTree *HT,int g,int &s1,int &s2)
{
    int i,j,k,m,n;
    for(k=1;k<=g;k++)
    {
        if(HT[k].parent==0)
        {
            s1=k;
            break;
        }
    }
   
    for(j=i;j<=g;j++)
    {
        if((HT[j].weight<=HT[k].weight)&&(HT[j].parent==0))
        s1=j;
    }
   
    for(m=1;m<=g;m++)
    {
        if((HT[m].parent==0)&&(m!=s1))
        {
            s2=m;
            break;
        }
    }
    for(n=1;n<=g;n++)
    {
        if((HT[n].weight<=HT[m].weight)&&(HT[n].parent==0)&&(n!=s1))
        s2=n;
    }
}

void CharSetHuffmanEncoding(HuffmanTree *T,HuffmanCode *H)      
{
    int c,p,i,n;
    char a,cd[6];
    int start;
    cd[5]='\n';
    printf("请输入字符的种类数：");          //问题所在处
    scanf("%d",&n);
    printf("%d",n);
    for(i=1;i<=n;i++)
    {
        printf("请输入对应权值的字符：");
        a=getchar();
        H[i]->ch='a';
        start=5;
        c=i;
        while(p=T[c].parent>0)
        {
            if(T[p].lchild==c)
            {
                cd[--start]='0';
            }
            else{
                cd[--start]='1';
            }
            c=p;
        }
    strcpy(H[i]->bits,cd);   
    }
}
int main()
{
    HuffmanTree T[MaxSize];
    HuffmanCode H[6];
    int leaf_num;
    int i,s1,s2;
    Count();
    printf("请输入叶子数：");
    scanf("%d",&leaf_num);
    CreateHuffmanTree(T,leaf_num);
    CharSetHuffmanEncoding(T,H);
    for(i=1;i<=leaf_num;i++)
    {
        printf("%c",H[i]->ch);
        printf("%s",H[i]->bits);
    }
    return 0;
}

忘了说了，程序里面有些输出变量的函数，查错用的，有点突兀

parent==0就跳出循环了啊。。。。

调试两天了，不知道是什么问题，心好累。各位大神帮忙看看啊。。。。

好的，我在试试看，谢谢