哈夫曼编码算

实验三树的应用

一.实验题目：

树的应用——哈夫曼编码

二.实验内容：

利用哈夫曼编码进行通信可以大大提高信道的利用率，缩短信息传输的时间，降低传输成本。根据哈夫曼编码的原理，编写一个程序，在用户输入结点权值的基础上求哈夫曼编码。

要求：从键盘输入若干字符及每个字符出现的频率，将字符出现的频率作为结点的权值，建立哈夫曼树，然后对各个字符进行哈夫曼编码，最后打印输出字符及对应的哈夫曼编码。

三、程序源代码:

#include

#include

#include

#include

typedef struct{

char data;

int weight;

int parent,lchild,rchild;

}HTNode,*HuffmanTree;

typedef char * * HuffmanCode;

void Select(HuffmanTree &HT,int n,int m)

{HuffmanTree p=HT;

int tmp;

for(int j=n+1;j<=m;j++)

{int tag1,tag2,s1,s2;

tag1=tag2=32767;

for(int x=1;x<=j-1;x++)

{ if(p[x].parent==0&&p[x].weight

{ tag1=p[x].weight;s1=x;}

}

for(int y=1;y<=j-1;y++)

{ if(p[y].parent==0&&y!=s1&&p[y].weight

{ tag2=p[y].weight;s2=y;}

}

if(s1>s2) //将选出的两个节点中的序号较小的始终赋给s1

{ tmp=s1; s1=s2; s2=tmp;}

p[s1].parent=j;

p[s2].parent=j;

p[j].lchild=s1;

p[j].rchild=s2;

p[j].weight=p[s1].weight+p[s2].weight;

}

}

void HuffmanCoding(HuffmanTree &HT,int n,char *w1,int*w2) {

int m=2*n-1;

if(n<=1) return;

HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));

HuffmanTree p=HT;

for(int i=1;i<=n;i++)

{ p[i].data=w1[i-1];

p[i].weight=w2[i];

p[i].parent=p[i].lchild=p[i].rchild=0;

}

for(;i<=m;i++)

{ p[i].weight=p[i].parent=p[i].lchild=p[i].rchild=0; } Select(HT,n,m);

ofstream outfile; //生成hfmTree文件

outfile.open("hfmTree.txt",ios::out);

for (i=1;i<=m;i++)

{outfile<

}

outfile.close();

cout<<"初始化结果已保存在hfmTree文件中\n";

}

void ToBeTree() //将正文写入文件ToBeTree中{

ofstream outfile;

outfile.open("ToBeTree.txt",ios::out);

outfile<<"THIS PROGRAM IS MYFA VORITE";

outfile.close();

}

void Encoding(HuffmanTree &HT,int n) //编码

{

HuffmanCode HC;

HC=(HuffmanCode)malloc((n+1)*sizeof(char *));

char *cd;

cd=(char *)malloc(n*sizeof(char));

cd[n-1]='\0';

for(int k=1;k<=n;k++)

{ int start=n-1;

for(int c=k,f=HT[k].parent;f!=0;c=f,f=HT[f].parent)

{ if(HT[f].lchild==c) cd[--start]='0';

else cd[--start]='1';

}

HC[k]=(char *)malloc((n-start)*sizeof(char));

strcpy(HC[k],&cd[start]);

}

cout<<"输出哈夫曼编码:"<

for(int h=1;h<=n;h++) //输出编码

{ cout<

cout<

cout<<" ";

if (h%8==0) cout<

}

cout<

ToBeTree();

//读取TOBETREE文件里的正文，并进行编码

fstream infile;

infile.open("ToBeTree.txt",ios::in);

char s[80];

while(!infile.eof())

{infile.getline(s,sizeof(s));}

infile.close();

fstream outfile;

outfile.open("CodeFile.txt",ios::out);

int count=0;

for (h=0;s[h]!='\0';h++)

{ for(k=1;k<=n;k++)

if (s[h]==HT[k].data)

{ cout<

cout<<" ";

count++;

outfile<

break;

}

if (count%9==0) cout<

outfile.close();

cout<<"\n编码结果已保存在文件CodeFile中.";