哈夫曼编码实验报告

数据结构实验班级:软件C092姓名:孙琼芳学号:098586试验目标利用哈夫曼编码进行通信能够大大提升信道利用率，缩短信息传输时间，降低传输成本。不过，这要求在发送端经过一个编码系统对待传数据预先编码，在接收端将传来数据进行译码（复原）。对于双工信道（即能够双向传输信息信道），每端都需要一个完整编码/译码系统。试为这么信息收发站写一个哈夫曼编码编码/译码器。源程序#include<iostream.h>#include<iomanip.h>#include<string.h>#include<malloc.h>#include<stdio.h>//typedefintTElemType;constintUINT_MAX=1000;charstr[50];typedefstruct{intweight,K;intparent,lchild,rchild;}HTNode,*HuffmanTree;typedefchar**HuffmanCode;//-----------全局变量-----------------------HuffmanTreeHT;HuffmanCodeHC;intw[50],i,j,n;charz[50];intflag=0;intnumb=0//-----------------求哈夫曼编码-----------------------structcou{chardata;intcount;}cou[50];intmin(HuffmanTreet,inti){//函数voidselect()调用intj,flag;intk=UINT_MAX;//取k为大于可能值,即k为最大权值1000for(j=1;j<=i;j++)if(t[j].weight<k&&t[j].parent==0)k=t[j].weight,flag=j;t[flag].parent=1;returnflag;}//--------------------slect函数----------------------voidselect(HuffmanTreet,inti,int&s1,int&s2){//s1为最小两个值中序号小那个intj;s1=min(t,i);s2=min(t,i);if(s1>s2){j=s1;s1=s2;s2=j;}}-voidHuffmanCoding(HuffmanTree&HT,HuffmanCode&HC,int*w,intn){//w存放n个字符权值(均>0),结构哈夫曼树HT,并求出n个字符哈夫曼编码HCintm,i,s1,s2,start;//unsignedc,f;intc,f;HuffmanTreep;char*cd;if(n<=1)return;//检测结点数是否能够组成树m=2*n-1;HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));//0号单元未用for(p=HT+1,i=1;i<=n;++i,++p,++w){p->weight=*w;p->parent=0;p->lchild=0;p->rchild=0;}for(;i<=m;++i,++p)p->parent=0;for(i=n+1;i<=m;++i)//建哈夫曼树{//在HT[1~i-1]中选择parent为0且weight最小两个结点,其序号分别为s1和s2select(HT,i-1,s1,s2);HT[s1].parent=HT[s2].parent=i;HT[i].lchild=s1;HT[i].rchild=s2;HT[i].weight=HT[s1].weight+HT[s2].weight;}//从叶子到根逆向求每个字符哈夫曼编码HC=(HuffmanCode)malloc((n+1)*sizeof(char*));//分配n个字符编码头指针向量([0]不用)cd=(char*)malloc(n*sizeof(char));//分配求编码工作空间cd[n-1]='\0';//编码结束符for(i=1;i<=n;i++){//逐一字符求哈夫曼编码start=n-1;//编码结束符位置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';elsecd[--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]);//从cd复制编码(串)到HC}free(cd);//释放工作空间}//---------------------获取报文并写入文件---------------------------------intInputCode(){//cout<<"请输入你想要编码字符"<<endl;FILE*tobetran;if((tobetran=fopen("tobetran.txt","w"))==NULL){cout<<"不能打开文件"<<endl;return0;}cout<<"请输入你想要编码字符"<<endl;gets(str);fputs(str,tobetran);cout<<"获取报文成功"<<endl;fclose(tobetran);returnstrlen(str);}//--------------初始化哈夫曼链表---------------------------------voidInitialization(){inta,k,flag,len;a=0;len=InputCode();for(i=0;i<len;i++){k=0;flag=1;cou[i-a].data=str[i];cou[i-a].count=1;while(i>k){if(str[i]==str[k]){a++;flag=0;}k++;if(flag==0)break;}if(flag){for(j=i+1;j<len;j++){if(str[i]==str[j])++cou[i-a].count;}}}n=len-a;for(i=0;i<n;i++){cout<<cou[i].data<<"";cout<<cou[i].count<<endl;}for(i=0;i<=n;i++){*(z+i)=cou[i].data;*(w+i)=cou[i].count;}HuffmanCoding(HT,HC,w,n);//------------------------打印编码-------------------------------------------cout<<"字符对应编码为:"<<endl;for(i=1;i<=n;i++){puts(HC[i]);}//--------------------------将哈夫曼编码写入文件------------------------cout<<"下面将哈夫曼编码写入文件"<<endl<<"...................."<<endl;FILE*htmTree;charr[]={'','\0'};if((htmTree=fopen("htmTree.txt","w"))==NULL){cout<<"cannotopenfile"<<endl;return;}fputs(z,htmTree);for(i=0;i<n+1;i++){fprintf(htmTree,"%6d",*(w+i));fputs(r,htmTree);}for(i=1;i<=n;i++){fputs(HC[i],htmTree);fputs(r,htmTree);}fclose(htmTree);cout<<"已将字符与对应编码写入根目录下文件htmTree.txt中"<<endl<<endl;}//---------------------编码函数---------------------------------voidEncoding(){cout<<"下面对目录下文件tobetran.txt中字符进行编码"<<endl;FILE*tobetran,*codefile;if((tobetran=fopen("tobetran.txt","rb"))==NULL){cout<<"不能打开文件"<<endl;}if((codefile=fopen("codefile.txt","wb"))==NULL){cout<<"不能打开文件"<<endl;}char*tran;i=99;tran=(char*)malloc(100*sizeof(char));while(i==99){if(fgets(tran,100,tobetran)==NULL){cout<<"不能打开文件"<<endl;break;}for(i=0;*(tran+i)!='\0';i++){for(j=0;j<=n;j++){if(*(z+j-1)==*(tran+i)){fputs(HC[j],codefile);if(j>n){cout<<"字符错误，无法编码!"<<endl;break;}}}}}cout<<"编码工作完成"<<endl<<"编码写入目录下codefile.txt中"<<endl<<endl;fclose(tobetran);fclose(codefile);free(tran);}//-----------------译码函数---------------------------------voidDecoding(){cout<<"下面对根目录下文件codefile.txt中字符进行译码"<<endl;FILE*codef,*txtfile;if((txtfile=fopen("txtfile.txt","w"))==NULL){cout<<"不能打开文件"<<endl;}if((codef=fopen("codefile.txt","r"))==NULL){cout<<"不能打开文件"<<endl;}char*work,*work2,i2;inti4=0,i,i3;unsignedlonglength=10000;work=(char*)malloc(length*sizeof(char));fgets(work,length,codef);work2=(char*)malloc(length*sizeof(char));i3=2*n-1;for(i=0;*(work+i-1)!='\0';i++){i2=*(work+i);if(HT[i3].lchild==0){*(work2+i4)=*(z+i3-1);i4++;i3=2*n-1;i--;}elseif(i2=='0')i3=HT[i3].lchild;elseif(i2=='1')i3=HT[i3].rchild;}*(work2+i4)='\0';fputs(work2,txtfile);cout<<"译码完成"<<endl<<"内容写入根目录下文件txtfile.txt中"<<endl<<endl;free(work);free(work2);fclose(txtfile);fclose(codef);}//-----------------------打印编码函数----------------------voidCode_printing(){cout<<"下面打印根目录下文件CodePrin.txt中编码字符"<<endl;FILE*CodePrin,*codefile;if((CodePrin=fopen("CodePrin.txt","w"))==NULL){cout<<"不能打开文件"<<endl;return;}if((codefile=fopen("codefile.txt","r"))==NULL){cout<<"不能打开文件"<<endl;return;}char*work3;work3=(char*)malloc(51*sizeof(char));do{if(fgets(work3,51,codefile)==NULL){cout<<"不能读取文件"<<endl;break;}fputs(work3,CodePrin);puts(work3);}while(strlen(work3)==50);free(work3);cout<<"打印工作结束"<<endl<<endl;fclose(CodePrin);fclose(codefile);}//-------------------------------打印译码函数---------------------------------------------voidCode_printing1(){cout<<"下面打印根目录下文件txtfile.txt中译码字符"<<endl;FILE*CodePrin1,*txtfile;if((CodePrin1=fopen("CodePrin1.txt","w"))==NULL){cout<<"不能打开文件"<<endl;return;}if((txtfile=fopen("txtfile.txt","r"))==NULL){cout<<"不能打开文件"<<endl;return;}char*work5;work5=(char*)malloc(51*sizeof(char));do{if(fgets(work5,51,txtfile)==NULL){cout<<"不能读取文件"<<endl;break;}fputs(work5,CodePrin1);puts(work5);}while(strlen(work5)==50);free(work5);cout<<"打印工作结束"<<endl<<endl;fclose(CodePrin1);fclose(txtfile);}//------------------------打印哈夫曼树函数-----------------------voidcoprint(HuffmanTreestart,HuffmanTreeHT){if(start!=HT){FILE*TreePrint;if((TreePrint=fopen("TreePrint.txt","a"))==NULL){cout<<"创建文件失败"<<endl;return;}numb++;//该变量为已被申明为全局变量coprint(HT+start->rchild,HT);cout<<setw(5*numb)<<start->weight<<endl;fprintf(TreePrint,"%d\n",start->weight);coprint(HT+start->lchild,HT);numb--;fclose(TreePrint);}}voidTree_printing(HuffmanTreeHT,intw){HuffmanTreep;p=HT+w;cout<<"下面打印哈夫曼树"<<endl;coprint(p,HT);cout<<"打印工作结束"<<endl;}//------------------------主函数------------------------------