huffman code.cpp

一个huffman 树的完整算法。用链表实现的c＋＋源程序

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAX 20 
typedef struct
{
	char name;
	unsigned int weight;
    unsigned int parent,lchild,rchild;
}HTNode,*HuffmanTree;
typedef char **HuffmanCode;
int min(HuffmanTree t,int i)
{
	int j,flag;
	unsigned int k=100;
	for(j=1;j<=i;j++)
		if(t[j].weight<k&&t[j].parent==0)
		{
			k=t[j].weight;
			flag=j;
		}
		t[flag].parent=1;
		return flag;
}
void select(HuffmanTree t,int i,int &s1,int &s2)
{
	int j;
	s1=min(t,i);
	s2=min(t,i);
	if(s1>s2)
	{
		j=s1;
		s1=s2;
		s2=j;
	}
}
void HuffmanCoding(HuffmanTree &HT,HuffmanCode &HC,int *w,int n,char (*na)[20])
{
	int m,i,s1,s2,start;
	unsigned c,f;
	HuffmanTree p;
	char *cd;
	if(n<=1)
		return;
	m=2*n-1;
	HT=(HuffmanTree)malloc((m+1)*sizeof(HTNode));
	for(p=HT+1,i=1;i<=n;++i,++p,++w)
	{
		(*p).name=(*na)[20];
		(*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)
	{
		select(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;
	}
	HC=(HuffmanCode)malloc((n+1)*sizeof(char*));
	cd=(char*)malloc(n*sizeof(char));
	cd[n-1]='\0';
	for(i=1;i<=n;i++)
	{
		start=n-1;
		for(c=i,f=HT[i].parent;f!=0;c=f,f=HT[f].parent)
			if(HT[f].lchild==c)
				cd[--start]='0';
			else
				cd[--start]='1';
			HC[i]=(char*)malloc((n-start)*sizeof(char));
			strcpy(HC[i],&cd[start]);
	}
	free(cd);
}
void input(HuffmanTree &s,char &c,int length,HuffmanTree &HT,HuffmanCode &HC,int n)
{
	int i,j;
	char cc[20];
	for(i=1;i<length;i++,c++)
		cc[i]=c;
	for(i=1;i<length;i++)
		if(cc[i]==HT[i].name)
			for(j=1;j<=n;j++)
				puts(HC[j]);
}
void ctoi(HuffmanTree &HT,HuffmanCode &HC,int n)
{
	char ch[20];
	char *cc;
	int i=0,length;
	HuffmanTree s;
	printf("请输入字符: ");
	scanf("%s",ch);
	cc=ch;
	length=strlen(ch);
	input(s,*cc,length,HT,HC,n);
}

void itoc(HuffmanTree &HT,HuffmanCode &HC,int n)
{
	char c[100];
	int i,nn;
	printf("待译字符个数:");
	scanf("%d",&nn);
	printf("请输入数字(不超过100):");
	for(i=0;i<nn;i++)
		scanf("%c",&c[i]);
		printf("此功能未能实现！");

}
void main()
{
	HuffmanTree HT;
	HuffmanCode HC;
	int *w,n,i;
	char na[MAX][20];
	char chc,chn;
	printf("请输入权值的个数(20>n>1)：");
	scanf("%d",&n);
	if (n<2)
	{
		printf("n必须大于1!\n");
		exit(1);
	}
	w=(int*)malloc(n*sizeof(int));
	printf("请依次输入%d个权值(整型)：\n",n);
	for(i=0;i<=n-1;i++)
	{
		printf("第%d个权值为：",i+1);
		scanf("%d",w+i);
		printf("               请输入名称：");
		scanf("%s",na[i]);
	}
	HuffmanCoding(HT,HC,w,n,na);
	for(i=1;i<=n;i++)
		puts(HC[i]);
	printf("是否继续?Y/N\n");
	scanf("%1s",&chc);
	if (chc=='Y'||chc=='y')
	{
		printf("1,编码   2,译码:");
		scanf("%1s",&chn);
		switch(chn)
		{
		case '1': ctoi(HT,HC,n);break;
 		case '2': itoc(HT,HC,n);break;
		}
	}
	else
		exit(1);
}