哈夫曼编译码
⑴ 哈夫曼编码与译码
#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <stdlib.h>
#include <conio.h>
#define NN 10000
#define M 2*NN-1
#define IN 0
#define OUT 1
#define MAX_INT 32767
#define PRINTLN printf("\n\n\n\n\n\n\n\n");
typedef struct
{
int wi;
char c;
int tag;
int parent, lchild, rchild;
}huffmtype;
typedef char* encodetype[NN+1];
typedef struct
{
char c;
int times;
}codetype;
void PRINT()
{
PRINTLN;
printf("\t\t\t Huffman编/译码器\n");
printf("\t\t\t ====================\n");
printf("\t\t\t 1.编码 2.译码 3.退出\n\n");
printf("\t\t\t >>选择:");
}
FILE* OpenFile(char filename[20], char type[3])
{
FILE *fp = NULL;
if((fp = fopen(filename, type)) == NULL) exit(1);
return fp;
}
int ReadCode(codetype* code, FILE* fp)
{
char c;//保存某次从文件中读入字符-
int n = 1;//记录首次出现字符在数组中的下标-
int i;//循环变量-
int cnt = 1;
int tag;//标志某次读入字符是否为首次出现字符，tag=1表示是首次出现;tag=0表示本次读入字符为已有字符
while((c = fgetc(fp)) != EOF)//当文件没有结束时读入字符-
{
//从fp指向文件中读取字符，存入字符变量c中-
tag = 1;//假设本次读取字符为首次出现字符-
for(i = 1; i < n; i++)
{
if(c == code[i].c)//如果本次读入字符为存储在下标为i已有字符-
{
code[i].times++;//权值加1-
tag = 0;//标记本字符为已有字符-
break;//在已有数组元素中找到本次读入字符，结束for(;;)循环-
}
}
if(tag)//当本字符为首次出现字符时-
{
code[n].c = c;//把改字符存入n指向的数组单元中-
code[n].times = 1;//记字符出现次数为1-
n++;//n指向下一个数组地址-
}
}
return n - 1;//返回文件中字符集合的元素个数-
}
void InitHuffmanTree(huffmtype* huffmtree, int real_n, int real_m)//初始化-
{
int i;
for(i = real_n; i <= real_m; i++)
{
huffmtree[i].wi = 0;
huffmtree[i].c = 0;
huffmtree[i].tag = IN;
huffmtree[i].lchild = huffmtree[i].rchild = huffmtree[i].parent = 0;
}
}
void ReadDataWeight_Init(huffmtype* huffmtree, codetype* code, int real_n)//获取权值及数值域值-
{
int i;
for(i = 1; i <= real_n; i++)//-
{
huffmtree[i].wi = code[i].times;
huffmtree[i].c = code[i].c;
huffmtree[i].tag = IN;
huffmtree[i].lchild = huffmtree[i].rchild = huffmtree[i].parent = 0;
}
}
int LeastNode(huffmtype *huffmtree, int max_i)//找到最小权值节点地址-
{
int i;
int least_i;
int max = MAX_INT;
for(i = 1; i <= max_i; i++)//遍历1到max_i节点-
{
if(huffmtree[i].wi < max && huffmtree[i].tag == IN)//若节点权值比max小并且在森林中-
{
max = huffmtree[i].wi;//刷新max值-
least_i = i;//保存当前节点地址-
}
}
huffmtree[least_i].tag = OUT;//将最小权值节点从森林中移除-
return least_i;//返回最小节点地址
}
void Slect(huffmtype *huffmtree, int max_i, int *x1, int *x2)//找到权值最小的两个节点，并将其下标值保存在x1，x2中-
{
*x1 = LeastNode(huffmtree, max_i);//计算合法最下权值下标-
*x2 = LeastNode(huffmtree, max_i);//
}
void CreatHuffmanTree(huffmtype* huffmtree, int real_n, int real_m)//创建哈弗曼树-
{
int i;
int x1, x2;
for(i = real_n + 1; i <= real_m; i++)
{
Slect(huffmtree, i-1, &x1, &x2);//找到权值最小的两个节点，并将其下标值保存在x1，x2中-
huffmtree[i].wi = huffmtree[x1].wi + huffmtree[x2].wi;//计算双气节点权值-
huffmtree[x1].parent = huffmtree[x2].parent = i;//计算双亲节点地址-
huffmtree[i].lchild = x1; huffmtree[i].rchild = x2;//计算双亲节点左右孩子地址-
}
}
void Encode(huffmtype *huffmtree, encodetype encode, int real_n)//依据已创建的HuffmanTree对字符进行编码-
{
char *cd;
int i;
int start;
int c, p;
cd = (char*)malloc(real_n*sizeof(char));//cd用来存放某次运行时当前字符编码-
cd[real_n - 1] = '\0';//作为字符结束符-
for(i = 1; i <= real_n; i++)//对real_n个节点进行遍历-
{
start = real_n-1;
c = i;//c保存当前节点地址（下标）-
p = huffmtree[i].parent;//p保存当前节点双亲地址-
while(p)
{
start--;//计算编码的起始地址-
if(huffmtree[p].lchild == c)//若当前节点为其双亲的左孩子-
{
cd[start] = '0';//编码为0-
}
else//若为右孩子-
{
cd[start] = '1';//编码为1-
}
c = p;//节点前进-
p = huffmtree[p].parent;//计算前进后节点双亲节点地址-
}
encode[i] =(char*)malloc((real_n - start)*sizeof(char));//申请空间用于存放编码-
strcpy(encode[i], &cd[start]);//将本次编码存入encode数组中-
}
free(cd);//释放闲置存储空间-
}
void WriteToFile(FILE *fp, encodetype encode, codetype *code, int real_n, char *readfile)//将编码输出到文件
{
int i;
char cod[NN];
FILE *fp2;
char c;
int cnt = 1, j;
fp2 = fopen(readfile, "rt");
while((c = fgetc(fp2)) != EOF)
{
cod[cnt++] = c;
}
fclose(fp2);
for(i = 1; i < cnt; i++)
{
for(j = 1; j <=real_n; j++)
{
if(cod[i] == code[j].c)
{
break;
}
}
fprintf(fp, "%s", encode[j]);
}
fclose(fp);
}
int IsError(FILE *fp)//对打开文件进行出错判断-
{
if(!fp)
{
printf("\t\t\t ×打开文件错误\n");
printf("\t\t\t 任意键返回主菜单");
getch();
return 1;//文件打开失败-
}
return 0;//文件打开成功-
}
void GetFilename(char *filename, char type[13])//得到用户输入相关文件名
{
system("cls");
PRINTLN;
printf("\t\t\t %s:", type);
fflush(stdin);
gets(filename);
}
int PutIntoCode(codetype code[], huffmtype huffmtree[])//编码函数
{
encodetype encode;
FILE* fp;//文件类型指针-
int real_n;//用来存放字符集长度-
char readfile[20];//从readfile文件中读取字符，写入到writefile文件中-
GetFilename(readfile, "读取源文件");//从键盘读取文件名-
fp=OpenFile(readfile, "rt");//打开待编码文件-
if(IsError(fp))//判断是否正确打开文件-
{
return 0;//打开文件失败，返回主菜单-
}
real_n=ReadCode(code, fp);//从readfile文件读取字符，将字符集合元素存入code数组，将集合元素个数存入real_n-
fclose(fp);//关闭文件-
ReadDataWeight_Init(huffmtree, code, real_n);//初始化HuffmanTree中从1到real_n的元素-
InitHuffmanTree(huffmtree, real_n, 2*real_n-1);//初始化HuffmanTree中real_n到2*real_n的元素-
CreatHuffmanTree(huffmtree, real_n, 2 * real_n - 1);//创建HuffmanTree-
Encode(huffmtree, encode, real_n);//根据HuffmanTree对字符进行编码，编码结果保存到encode数组中-
fp = OpenFile("CodeFile.txt", "wb");//打开待写入文件-
WriteToFile(fp, encode, code, real_n, readfile);//将encode数组中元素写入到文件中-
fclose(fp);//关闭文件-
printf("\t\t\t 完成编码并保存至CodeFile.txt文件中");//打印完成编码信息-
getch();//等待用户输入任意键返回主菜单-
return real_n;
}
void Translate(codetype code[], huffmtype huffmtree[], int real_n)//译码函数
{
FILE *fp,*fp2;
int i, real_m;
char c;
char writefile[20];
GetFilename(writefile, "保存解码文件到");
fp = OpenFile("CodeFile.txt", "rb");
fp2 = OpenFile(writefile, "wt");
if(IsError(fp))
{
return;
}
i = real_m = 2*real_n - 1;
while((c = fgetc(fp)) != EOF)
{
if(c == '0')
{
i = huffmtree[i].lchild;
}
else
{
i = huffmtree[i].rchild;
}
if(huffmtree[i].lchild == 0)
{
fputc(code[i].c, fp2);
i = real_m;
}
}
fclose(fp);
fclose(fp2);
printf("\t\t\t 完成译码任务");
getch();
}
int main(void)
{
int choice;
int real_n = 0;
codetype code[NN];
huffmtype huffmtree[NN];
while(1)
{
system("cls");
PRINT();
scanf("%d",&choice);
switch(choice)
{
case 1 :
real_n = PutIntoCode(code, huffmtree);
break;//编码函数
case 2 :
if(real_n) Translate(code, huffmtree, real_n);break;//译码函数
case 3 :
exit(1);//退出程序
default :
printf("\t\t\t ★无效输入");
getch();
break;
}
}
return 0;
}
⑵ 哈夫曼编/译码系统的主要思想
1、是一种利用二叉树实现的编码原理
霍夫曼（Huffman）编码原理
霍夫曼（Huffman）编码是1952年为文本文件而建立，是一种统计编码。属于无损压缩编码。
霍夫曼编码的码长是变化的，对于出现频率高的信息，编码的长度较短；而对于出现频率低的信息，编码长度较长。这样，处理全部信息的总码长一定小于实际信息的符号长度。
⑶ 哈夫曼编码/译码器
注释非常详细，希望对你有所帮助！
#ifndef Huffman_Tree_h
#define Huffman_Tree_h
#endif
#include <stdio.h>
typedef struct {
unsigned int weight;
unsigned int parent,lchild,rchild;
}HTNode, * HuffmanTree; //存储赫夫曼树的结点类型
typedef char * * HuffmanCode; //用于存储字符集中各个字符相应的赫夫曼编码
void strcpy(char *S1,char *S2){ //将字符串S2复制到S1
int i = 0;
while( S2[i] != '\0' ){
S1[i] = S2[i];
i++;
}
S1[i] = '\0';
}
void Select(HuffmanTree HT,int t,int &s1,int &s2){ //在HT[1]到HT[t-1]中找出权值最小的两个S1和S2
int i = 1;
s1 = s2 = 0;
HT[0].weight = 65535;
while( i <= t ){ //遍历查找权值最小的结点S1
if( HT[i].parent == 0 && HT[i].weight < HT[s1].weight )
s1 = i;
i++;
}
i = 1;
while( i <= t ){ //遍历查找除S1外权值最小的结点S2
if( i != s1 && HT[i].parent == 0 && HT[i].weight < HT[s2].weight )
s2 = i;
i++;
}
}
int HuffmanCoding( HuffmanTree &HT,HuffmanCode &HC,int *w,int n){ //根据各个字符的权值构造赫夫曼树HT，将对应的赫夫曼编码存储在HC中
int s1,s2,m,i,start;
unsigned int c,f;
HTNode * p;
char *cd;
if( n <= 1 ) return 0;
m = 2 * n - 1; //赫夫曼树的总结点树为m
HT = (HuffmanTree)malloc((m + 1) * sizeof(HTNode)); //申请存储赫夫曼树的空间
for(p = HT + 1, i = 1; i <= n; ++i, ++p, ++w){ //将各个叶子结点的weight赋以相应的权值，parent,lchild,rchild均赋为0
p->weight = *(w+1);
p->parent = p->lchild = p->rchild = 0;
}
for( ; i <= m; ++i, ++p ){ //将各个非叶子结点的weight,parent,lchild,rchild均赋为0
p->weight = p->parent = p->lchild = p->rchild = 0;
}
for( i = n + 1; i <= m; ++i ){ //构造赫夫曼树，给各个非叶子结点赋值
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 *)); //申请空间，用于存储指向存储各个字符相应赫夫曼编码的字符数组的指针
cd = (char *)malloc(n * sizeof(char)); //申请用于求赫夫曼编码
cd[n - 1] = '\0'; //编码结束符
for( i = 1; i <= n; ++i){ //逐个字符求赫夫曼编码
start = n -1; //编码在数组cd[]中的最前位置
for(c = i,f = HT[i].parent; f != 0; c = f, f = HT[f].parent) //从叶子到根逆向求编码
if(HT[f].lchild == c)
cd[ --start ] = '0';
else
cd[ --start ] = '1';
HC[i] = (char *)malloc((n - start)*sizeof(char)); //为第i个字符编码分配空间
strcpy(HC[i], &cd[start]); //将cd[]数组的start位置到n-1位置复制给HC[i]
}
free(cd); //释放空间
return 1;
}
以上为第一部分
#include <stdio.h>
#include <stdlib.h>
#include "Huffman_Tree.h"
#define Yes 1 //当程序已经调用过初始化赫夫曼树的InitHuff_T()函数，或已从htfTree文件读取过，则将Init_Mode置为Yes，否则为No
#define No 0
void InitHuff_T( HuffmanTree &HT, HuffmanCode &HC, char ch[],int &n ){ //初始化赫夫曼数，要求用户输入字符和相应权值
int i = 1,w[100],tem,j;
char a[20];
FILE *save;
printf("请输入编码字符集的大小n:");
scanf("%d",&n); //获取用户输入的字符集个数
while( i <= n ){ //获取用户输入的字符和相应权值，分别存储在ch[]和w[]数组中
printf("请输入第%d个字符和该字符的权值w:",i);
fflush(stdin);
scanf("%c%d",&ch[i],&w[i]);
i++;
}
ch[i] = '\0';
HuffmanCoding(HT,HC,w,n); //根据用户的输入，生成赫夫曼数及各个字符相应的赫夫曼编码，分别存在HT树和HC中
if(( save = fopen("htfTree","w")) == NULL ){ //打开用于存储赫夫曼树的文件
printf("Open file fail......\n");
exit(0);
}
tem = n; //接下来的14行是将字符集大小转换成字符形式写入到文件中
j = 0;
while( tem != 0 ){
tem = tem / 10;
j++;
}
tem = n;
a[j] = '\0';
while( tem != 0 ){
a[j - 1] = (char)(tem % 10 + 48);
tem = tem / 10;
j--;
}
fputs(a,save);
printf("%d\n",n); //向屏幕输出字符集大小n
fputc('\n',save);
for( i = 1; i <= n; i++ ){ //分别向文件和屏幕输出各个字符和相应的赫夫曼编码
fputc(ch[i],save); printf("%c\t",ch[i]);
fputc('\t',save);
fputs(HC[i],save); printf("%s\n",HC[i]);
fputc('\n',save);
}
for(i = 1; i <= 2 * n - 1; i++ ){ //将赫夫曼树各个结点的parent,lchild,rchild分别写入到文件中
tem = HT[i].parent; //将i结点的parent转换成字符并写入到文件中
if(tem == 0){
fputc(tem + 48,save);
fputc(' ',save);
}
else{
j = 0;
while( tem != 0 ){
tem = tem / 10;
j++;
}
tem = HT[i].parent;
a[j] = '\0';
while( tem != 0 ){
a[j - 1] = (char)(tem % 10 + 48);
tem = tem / 10;
j--;
}
fputs(a,save);
fputc(' ',save);
}
tem = HT[i].lchild; //将i结点的lchild转换成字符并写入到文件中
if(tem == 0){
fputc(tem + 48,save);
fputc(' ',save);
}
else{
j = 0;
while( tem != 0 ){
tem = tem / 10;
j++;
}
tem = HT[i].lchild;
a[j] = '\0';
while( tem != 0 ){
a[j - 1] = (char)(tem % 10 + 48);
tem = tem / 10;
j--;
}
fputs(a,save);
fputc(' ',save);
}
tem = HT[i].rchild; //将i结点的rchild转换成字符并写入到文件中
if(tem == 0){
fputc(tem + 48,save);
fputc('\n',save);
}
else{
j = 0;
while( tem != 0 ){
tem = tem / 10;
j++;
}
tem = HT[i].rchild;
a[j] = '\0';
while( tem != 0 ){
a[j - 1] = (char)(tem % 10 + 48);
tem = tem / 10;
j--;
}
fputs(a,save);
fputc('\n',save);
}
}
fclose(save);
}
void Encoding(HuffmanTree &HT, HuffmanCode &HC, char ch[]){ //根据赫夫曼编码将用户指定的文件中的字符编成相应的编码,并将所得编码存储到用户指定文件
FILE *ToBeTran,*CodeFile;
char ToBeTran_Name[100],CodeFile_Name[100]; //存储用户指定文件的文件名
int i;
char c;
printf("请输入所要进行编码的文件的文件名:");
scanf("%s",ToBeTran_Name); //获得所要进行编码的文件的文件名
if(( ToBeTran = fopen(ToBeTran_Name,"r")) == NULL ){ //打开文件
printf("Open file fail......\n");
exit(0);
}
printf("请输入编码后编码表示的信息所存储到的文件的文件名:");
scanf("%s",CodeFile_Name); //获得编码后编码表示的信息所存储到的文件的文件名
if(( CodeFile = fopen(CodeFile_Name,"w")) == NULL ){ //打开文件
printf("Open file fail......\n");
exit(0);
}
c = fgetc(ToBeTran); //从文件读取一个字符
while( c != EOF ){ //对文件中的各个字符进行编码，直至文件结尾
i = 1;
while( c != ch[i] && ch[i] != '\0' ) //在ch[]数组中查找从文件读取的字符
i++;
if(ch[i] == '\0'){ //未找到，c不在ch[]数组中，c无法被识别，程序出错，退出
printf("字符%c无法识别，程序将退出。\n",c);
exit(0);
}
fputs(HC[i],CodeFile); //若找到，则将c相应的赫夫曼编码写入到文件中
printf("%s",HC[i]); //将c相应的赫夫曼编码输出到屏幕
c = fgetc(ToBeTran); //读入文件中的下一个字符
}
printf("\n");
fclose(ToBeTran);
fclose(CodeFile);
}
void Decoding(HuffmanTree HT, char ch[] , int n){ //对指定的存储由赫夫曼编码表示的信息的文件进行译码，翻译成相应的字符表示，并存储到指定文件
int p,i = 1;
char code[1000],c;
char CodeFile_Name[100],TextFile_Name[100]; //存储用户指定文件的文件名
p = 2 * n - 1;
FILE *CodeFile,*TextFile;
printf("请输入所要译的文件名:");
scanf("%s",CodeFile_Name); //获得所要译的文件的文件名
if(( CodeFile = fopen("CodeFile","r")) == NULL ){ //打开文件
printf("Open file fail......\n");
exit(0);
}
printf("请输入译后的字符存储到的文件的文件名:");
scanf("%s",TextFile_Name); //获得译后的字符存储到的文件的文件名
if(( TextFile = fopen(TextFile_Name,"w")) == NULL ){ //打开文件
printf("Open file fail......\n");
exit(0);
}
c = fgetc(CodeFile);
while( c != EOF ){
code[i] = c;
i++;
c = fgetc(CodeFile);
}
code[i] = '\0'; //从文件读取字符，存储在code[]数组中
i = 1;
while ( code[i] != '\0' && p != 0 ){ //对数组code[]中的赫夫曼编码进行译码
if ( code[i] == '0' )
p=HT[p].lchild; //进入左分支
else
p = HT[p].rchild; //进入右分支
if (!HT[p].lchild&& !HT[p].rchild){ //进入叶子结点
fputc(ch[p], TextFile); //将相应的字符写入到文件中
printf("%c",ch[p]); //将相应的字符输出到屏幕
p = 2 * n - 1; //重新从树根出发进行译码
}
i++;
}
printf("\n");
}
void ReadHuff_T( HuffmanTree &HT, HuffmanCode &HC, char ch[], int &n){ //从文件读取赫夫曼树
FILE *htfTree;
char c[100],ch1;
int i,j,t;
if(( htfTree = fopen("htfTree","r")) == NULL ){ //打开存有赫夫曼树信息的文件
printf("Open file fail......\n");
exit(0);
}
fgets(c,10,htfTree); //获取赫夫曼树叶子结点个数的字符串表示形式
i = 0; //以下6行将字符串形式转换成整数形式
while( c[i] != '\n' )
i++;
n = 0;
for( j = 0; j < i; j++ )
n = 10 * n + c[j] - '0'; //求出叶子结点数n
HC = (HuffmanCode)malloc((n + 1) * sizeof(char *)); //申请HC空间
HT = (HuffmanTree)malloc((2 * n) * sizeof(HTNode)); //申请赫夫曼树存储空间
i = 1;
while( i <= n ){
ch[i] = fgetc(htfTree); //读取字符集中的一个字符
HC[i] = (char *)malloc((10)*sizeof(char)); //申请用于存储读取到的字符集中的字符的赫夫曼编码的空间
fgetc(htfTree); //将‘\t’输出
ch1 = fgetc(htfTree); //读取赫夫曼编码，存储在相应的HC[i][]数组里
int j = 0;
while( ch1 != '\n' ){
HC[i][j] = ch1;
j++;
ch1 = fgetc(htfTree);
}
HC[i][j] = '\0';
i++;
}
ch[i] = '\0';
i = 0;
while( i < 2 * n - 1 ){ //读取赫夫曼树的各个结点的parent,lchild,rchild.并赋值到赫夫曼树HT中
ch1 = fgetc(htfTree); //读取parent的字符串形式,存储在c[]中，并将其转换成整数形式，赋给HT[i].parent
j = 0;
while( ch1 != ' ' ){
c[j] = ch1;
j++;
ch1 = fgetc(htfTree);
}
HT[i+1].parent = 0;
for( t = 0; t < j; t++ )
HT[i+1].parent = 10 * HT[i+1].parent + c[t] - '0';
ch1 = fgetc(htfTree); //读取lchild的字符串形式，并将其转换成整数形式，赋给HT[i].lchild
j = 0;
while( ch1 != ' ' ){
c[j] = ch1;
j++;
ch1 = fgetc(htfTree);
}
HT[i+1].lchild = 0;
for( t = 0; t < j; t++ )
HT[i+1].lchild = 10 * HT[i+1].lchild + c[t] - '0';
ch1 = fgetc(htfTree); //读取rchild的字符串形式，并将其转换成整数形式，赋给HT[i].rchild
j = 0;
while( ch1 != '\n' ){
c[j] = ch1;
j++;
ch1 = fgetc(htfTree);
}
HT[i+1].rchild = 0;
for( t = 0; t < j; t++ )
HT[i+1].rchild = 10 * HT[i+1].rchild + c[t] - '0';
i++;
}
}
int main(){
HuffmanTree HT;
HuffmanCode HC;
char ch[100]; //用于存储字符集
int n,Init_Mode = No; //n为字符集的大小，Init_Mode = No 表示内存中没有赫夫曼树的信息
char mode; //让用户选择不同的操作
printf("请输入你要选择的功能\n");
printf("\t\tI -- 初始化\t\tE -- 编码\n");
printf("\t\tD -- 译码 \t\tQ -- 退出程序\n");
scanf("%c",&mode); //获得用户选择的操作
while( mode != 'Q' && mode != 'q' ){ //当用户输入不为Q或q时，执行相应操作
switch(mode){
case 'I' :
InitHuff_T(HT,HC,ch,n);
Init_Mode = Yes;
break;
case 'i' :
InitHuff_T(HT,HC,ch,n);
Init_Mode = Yes;
break;
case 'E' :
if( No == Init_Mode )
ReadHuff_T(HT,HC,ch,n);
Encoding(HT,HC,ch);
Init_Mode = Yes;
break;
case 'e' :
if( No == Init_Mode )
ReadHuff_T(HT,HC,ch,n);
Encoding(HT,HC,ch);
Init_Mode = Yes;
break;
case 'D' :
if( No == Init_Mode )
ReadHuff_T(HT,HC,ch,n);
Decoding(HT,ch,n);
Init_Mode = Yes;
break;
case 'd' :
if( No == Init_Mode )
ReadHuff_T(HT,HC,ch,n);
Decoding(HT,ch,n);
Init_Mode = Yes;
default :
printf("您的输入有错，请重新选择.\n");
}
printf("请输入你要选择的功能\n");
printf("\tI -- 初始化\tE -- 编码\n");
printf("\tD -- 译码 \tQ -- 退出程序\n");
fflush(stdin);
scanf("%c",&mode); //让用户继续选择相应的操作，直至用户选择退出
}
return 0;
}
⑷ 哈夫曼编/译码器是什么
这个是我课程设计弄的，也是哈弗曼编码译码器
#include<iostream>
#include<stdlib.h>
#include<string.h>
using namespace std;
typedef struct{
int weight;
int parent,lchild,rchild;
int asc;
}HTNode,*HuffmanTree; //定义赫夫曼存储结构
struct node{
int ASCII;
int n;
};
struct node a[127];
struct node w[127];
//一些全局变量
int count;
HTNode H_T[250];
char ** HC;
char filename[20];
//函数声明
void menu1(); //菜单1
HuffmanTree HeapSort(HuffmanTree HT,int length); //堆排序
void MinHeapify(HuffmanTree HT, int k,int len); //调整成一个小顶堆
void buildMinHeap(HuffmanTree HT,int len); //建一个小顶堆
void swap(HTNode &t1,HTNode &t2); //交换两结构体
void savefile(); //把输入的英文文章保存到文件
void loadfile(); //从文件中读取文章
HuffmanTree CreateHuffman(HuffmanTree &HT,struct node *w,int n); //建立赫夫曼数并存入文件
void BianMa(HuffmanTree HT,int n ); //字符编码
void BianMa_all(HuffmanTree HT,char**HC,char *filename); //整篇文章编码
int loadfile2(); //从文件读入文章
void JieMa(); //解码
//主函数
int main()
{
char s;
while(s!='0')
{
system("cls");
cout<<"\n\n\n";
cout<<"\t\t\t\t赫夫曼编码/译码器"<<endl<<endl<<endl<<endl<<endl;
cout<<"\t\t\t\t 1.编码"<<endl<<endl<<endl<<endl;
cout<<"\t\t\t\t 2.译码"<<endl<<endl<<endl<<endl;
cout<<"\t\t\t\t 0.退出"<<endl<<endl<<endl<<endl;
cout<<"\t请输入0—2进行选择，按回车确认";
cin>>s;
switch(s)
{
case '1': menu1(); break;
case '2':
{
system("cls");
JieMa();
system("pause");
break;
}
}
}
}
//菜单1
void menu1(){
char s;
int i;
int a;
char c;
char fpname[20]="article.txt";
HuffmanTree HT;
while(s!='0'){
system("cls");
cout<<"\n\t\t\t\t编码界面";
cout<<"\n\n\n\t\t\t\t1.输入英文文章"<<endl;
cout<<"\n\n\t\t\t\t2.从文件中读入文章"<<endl;
cout<<"\n\n\t\t\t\t0.返回上一层"<<endl;
cout<<"\n\t请输入0—2进行选择，按回车确认";
cin>>s;
switch(s){
case'1':
system("cls");
savefile();
loadfile();
CreateHuffman(HT,w,count);
BianMa(HT,count);
BianMa_all(HT,HC,fpname);
system("cls");
cout<<"出现字符种类共计：";
cout<<count<<endl;
for(i=1;i<=count;i++)
{ a=HT[i].asc;
c=(char)a;
cout<<"________________________________________________________________________________"<<endl;
cout<<"\t\t\t字符：";
cout<<c<<endl;
cout<<"\t\t\tASCII码：";
cout<<a<<endl;
cout<<"\t\t\t频数：";
cout<<HT[i].weight<<endl;
cout<<"\t\t\t赫夫曼编码：";
cout<<HC[i]<<endl;
}
cout<<"________________________________________________________________________________";
cout<<"\n\t\t整篇文章的编码已存入文件“赫夫曼编码.txt”"<<endl;
system("pause");
break;
case'2':
system("cls");
if(loadfile2())
{ system("pause");
return;}
CreateHuffman(HT,w,count);
BianMa(HT,count);
BianMa_all(HT,HC,filename);
system("cls");
cout<<"出现字符种类共计：";
cout<<count<<endl;
for(i=1;i<=count;i++)
{ a=HT[i].asc;
c=(char)a;
cout<<"________________________________________________________________________________"<<endl;
cout<<"\t\t\t字符：";
cout<<c<<endl;
cout<<"\t\t\tASCII码：";
cout<<a<<endl;
cout<<"\t\t\t频数：";
cout<<HT[i].weight<<endl;
cout<<"\t\t\t赫夫曼编码：";
cout<<HC[i]<<endl;
}
cout<<"________________________________________________________________________________";
cout<<"\n\t\t整篇文章的编码已存入文件“赫夫曼编码.txt”"<<endl;
system("pause");
break;
}
}
}
//交换结构体
void swap(HTNode &t1,HTNode &t2)
{
HTNode m;
m = t1;
t1 = t2;
t2 = m;
}
//从键盘输入文章并保存
void savefile(){
FILE *fp;
char article;
if((fp=fopen("article.txt","w"))==NULL){
printf("打开文件不成功！");
exit(0);
}
cout<<"请输入英文文章,以#结束:";
getchar();
article=getchar();
while(article!='#'){
fputc(article,fp);
article=getchar();
}
fclose(fp);
}
//从文件读取文章，并统计字符出现频数
void loadfile(){
FILE *fp;
char ch;
int i,k,j=0;
count=0;
for(i=0;i<=127;i++) //把所有字符的ascii码存在数组
{ a[i].ASCII=i;
a[i].n=0;
}
if((fp=fopen("article.txt","r"))==NULL){
printf("打开文件不成功！");
exit(0);
}
ch=fgetc(fp);
k=(int)ch;
a[k].n++;
while(!feof(fp)){
ch=fgetc(fp);
k=(int)ch;
a[k].n++;
}
fclose(fp);
for(i=0;i<=127;i++) //统计字符种类总数
{
ch=(char)i;
if(a[i].n){
count++;
}
}
for(i=0;i<=127;i++)
{
for(;j<count;)
{
if(a[i].n)
{
w[j].n=a[i].n;
w[j].ASCII=a[i].ASCII;
j++;
break;
}
else break;
}
}
}
//调整为小顶堆
void MinHeapify(HuffmanTree HT, int k,int len)
{
int left=k*2;
int right=k*2+1;
int large;
int l=len;
large = k;
if (left<=l&&HT[left].weight<HT[large].weight)
large = left;
if (right<=l&& HT[right].weight<HT[large].weight)
large=right;
if (large!=k)
{
swap(HT[k],HT[large]);
MinHeapify(HT,large,l);
}
}
//建立小顶堆
void buildMinHeap(HuffmanTree HT,int len)
{
int i;
for (i=len/2;i>=1;i--)
{
MinHeapify(HT,i,len);
}
}
//堆排序
HuffmanTree HeapSort(HuffmanTree HT,int length)
{
int i;
int l=length;
buildMinHeap(HT,length);
for (i=length;i>= 2;i--)
{
swap(HT[1],HT[i]);
length--;
MinHeapify(HT,1,length);
}
return HT;
}
//建立赫夫曼数
HuffmanTree CreateHuffman(HuffmanTree &HT,struct node *w,int n)
{
int i,m,s1,s2,k1,k2,j,x,a;
FILE *fp,*fp2;
if(n<=1) return HT;
m=2*n-1;
HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));//0不用
for(i=1,j=0;i<=n;i++,j++)
{ HT[i].asc=w[j].ASCII;
HT[i].weight=w[j].n;
HT[i].parent=0;
HT[i].lchild=0;
HT[i].rchild=0;
}
for(;i<=m;i++)
{ a=250+i;
HT[i].asc=a;//父亲节点的asc可以是大于127的任意值
HT[i].weight=0;
HT[i].parent=0;
HT[i].lchild=0;
HT[i].rchild=0;
}
for(i=1;i<=n;i++){
H_T[i].asc=HT[i].asc;
H_T[i].parent=HT[i].parent;
H_T[i].lchild=HT[i].lchild;
H_T[i].rchild=HT[i].rchild;
H_T[i].weight=HT[i].weight;
}
for(i=n+1,x=n;i<=m;i++,x--)
{
HeapSort(H_T,x);
k1=H_T[x].asc;
k2=H_T[x-1].asc;
for(j=1;j<=127;j++)
{
if(HT[j].asc==k1)
}
for(j=1;j<=127;j++)
{
if(HT[j].asc==k2)
}
HT[s2].parent=i;
HT[s1].parent=i;
HT[i].lchild=s1;
HT[i].rchild=s2;
HT[i].weight=HT[s1].weight+HT[s2].weight;
H_T[x-1].asc=HT[i].asc;
H_T[x-1].lchild=HT[i].lchild;
H_T[x-1].parent=HT[i].parent;
H_T[x-1].rchild=HT[i].rchild;
H_T[x-1].weight=HT[i].weight;
}
if((fp2=fopen("count.txt","w"))==NULL) //保存赫夫曼树
{
cout<<"文件打开不成功！"<<endl;
exit(0);
}
fputc(count,fp2);
if((fp=fopen("HuffmanTree.dat","wb"))==NULL)
{ cout<<"文件打开不成功！"<<endl;
exit(0);
}
for(i=1;i<=(2*count-1);i++){
fwrite(&HT[i],sizeof(HTNode),1,fp);
}
fclose(fp);
fclose(fp2);
return HT;
}
//逆向编码
void BianMa(HuffmanTree HT,int n){
char *cd,temp;
int c,f,i,j,len,p,q;
cd=(char *)malloc(n*sizeof(char));
HC=(char * *)malloc(n*sizeof(char*));
for(i=1;i<=n;i++){
for(c=i,f=HT[i].parent,j=0;f!=0;c=f,f=HT[f].parent,j++)
{ if(HT[f].lchild==c) cd[j]='0';
else cd[j]='1';
if(HT[f].parent==0)
cd[j+1]='\0';
}
len=strlen(cd);
for(p=0,q=len-1;p<=q;p++,q--)
{
temp=cd[q];
cd[q]=cd[p];
cd[p]=temp;
}
cd[len]='\0';
HC[i]=(char*)malloc((len+10)*sizeof(char));
strcpy(HC[i],cd);
}
}
//整篇文章编码，并存入文件
void BianMa_all(HuffmanTree HT,char**HC,char *filename){
char ch;
int k,i;
FILE *fp,*fp2;
char code[100];
if((fp=fopen(filename,"r"))==NULL){
printf("打开文件不成功！");
exit(0);
}
if((fp2=fopen("赫夫曼编码.txt","w"))==NULL){
printf("打开文件不成功！");
exit(0);
}
ch=fgetc(fp);
k=(int)ch;
while(!feof(fp))
{
for(i=1;i<=count;i++)
{
if(k==HT[i].asc)
strcpy(code,HC[i]);
}
fputs(code,fp2);
ch=fgetc(fp);
k=(int)ch;
}
fclose(fp);
fclose(fp2);
}
void JieMa(){
int i,k,a,t,n=0;
FILE *fp1,*fp2,*fp3;
char ch,c;
HuffmanTree ht;
if((fp3=fopen("count.txt","r"))==NULL) //从文件读出字符总数
{
printf("打开文件不成功！");
exit(0);
}
n=fgetc(fp3);
ht=(HuffmanTree)malloc(2*n*sizeof(HTNode));
if((fp1=fopen("赫夫曼编码.txt","r"))==NULL)
{
printf("打开文件不成功！");
exit(0);
}
if((fp2=fopen("HuffmanTree.dat","rb"))==NULL)
{ cout<<"文件打开不成功！"<<endl;
exit(0);
}
for(i=1;i<=2*n-1;i++)
fread(&ht[i],sizeof(HTNode),1,fp2);
for(i=1;i<=2*n-1;i++)
{
if(ht[i].parent==0)
}
ch=fgetc(fp1);
while(!feof(fp1)){
if(ch=='0')
{
k=ht[k].lchild;
if(ht[k].lchild==0)
{a=ht[k].asc;
c=(char)a;
printf("%c",c);;
k=t;
}
}
if(ch=='1')
{
k=ht[k].rchild;
if(ht[k].lchild==0)
{ a=ht[k].asc;
c=(char)a;
printf("%c",c);
k=t;
}
}
ch=fgetc(fp1);
}
fclose(fp1);
fclose(fp2);
}
//读取文件中的文章，可自己选择文件
int loadfile2(){
FILE *fp;
char ch;
int i,k,j=0;
count=0;
for(i=0;i<=127;i++)
{ a[i].ASCII=i;
a[i].n=0;
}
cout<<"\n\n\n\t\t\t请输入你要打开的文件名：";
cin>>filename;
if((fp=fopen(filename,"r"))==NULL){
printf("打开文件不成功！");
return 1;
}
ch=fgetc(fp);
k=(int)ch;
a[k].n++;
while(!feof(fp)){
ch=fgetc(fp);
k=(int)ch;
a[k].n++;
}
fclose(fp);
for(i=0;i<=127;i++){
ch=(char)i;
if(a[i].n){
count++;
}
}
for(i=0;i<=127;i++)
{
for(;j<count;)
{
if(a[i].n)
{
w[j].n=a[i].n;
w[j].ASCII=a[i].ASCII;
j++;
break;
}
else break;
}
}
return 0;
}
另外,站长团上有产品团购,便宜有保证