//生成HuffmanCode文件的两个函数
void HuffmanEncoding(HuffmanTree HT,HuffmanCode HC){//根据HuffmanTreeHT求HuffmanCode表HC
int c,p,i;
char cd[n];
int start;
cd[num] = '\0';
for(i = 1;i <= num;i++){
start = num;
c = i;
while((p = HT[c].parent) > 0){
cd[--start] = (HT[p].lchild == c)?'0':'1';
c = p;
}
strcpy(HC[i].bits,&cd[start]);
HC[i].len = num - start;
}
}
void coding(HuffmanCode HC,char *str){//对所代表的字符串进行编码，并写入文件
int i,j;
FILE *fp;
fp=fopen("codefile.txt","w");
while(*str){
for(i = 1;i <= num;i++){
if(HC[i].ch == *str){
for(j = 0;j < HC[i].len;j++)
fputc(HC[i].bits[j],fp);
break;
}
}str++;
}fclose(fp);
}
//电文的译码
char * decode(HuffmanCode HC){
FILE *fp;
char str[254];
char *p;
static char cd[n+1];
int i,j,k = 0,cjs;
fp = fopen("codefile.txt","r");
while(!feof(fp)){
cjs = 0;
for(i = 0;i < num&&cjs == 0&&!feof(fp);i++){
cd[i] = ' ';
cd[i+1] = '\0';
cd[i] = fgetc(fp);
for(j = 1;j <= num;j++){
if(strcmp(HC[j].bits,cd) == 0){
str[k] = HC[j].ch;
k++;
cjs = 1;
break;
}
}
}
}
str[k] = '\0';
p = str;
return p;
}
//测试主控函数
void main(){
char st[254],*s,str[27];
int cn[27];
HuffmanTree HT;
HuffmanCode HC;
printf("输入需要编码的字符串（假设均为大写字母）：\n");
gets(st);
num = jsq(st,cn,str);//统计字符的种类及各类字符出现的频率
CreHuffmanTree(HT,HC,cn,str);//建立赫夫曼树
HuffmanEncoding(HT,HC);//生成赫夫曼编码
coding(HC,st);//建立电文赫夫曼编码文件
s = decode(HC);//读编码文件译码
printf("译码后的字符串：%s\n",s);//输出译码后的字符串
printf("字符串长度：%d\n",strlen(s));
}
