C++ 哈弗曼编码的实现与反编码

文章由LinuxBoy分享于2019-04-01 01:04:31热评（229）

C++ 哈弗曼编码的实现与反编码

#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
void 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)
{ s1=j;break;}
}
for(j=1;j<=127;j++)
{
if(HT[j].asc==k2)
{ s2=j;break;}
}
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){t=k=i;break;}
}
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;
}

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