C语言：哈夫曼树的编码与译码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<conio.h>

#define N 100

typedef struct
{
	int weight;
	int parent, lchild, rchild;
}hafuman;

typedef struct
{
	char data[N]; //字符数据

	char copy[N][10*N];//编码
}bianma;

void display();
int input(int w[], bianma *bm);
void creat_hafuman(hafuman ht[], int w[], int n);
void select(hafuman ht[], int m, int *s1,  int *s2);
void encoding(hafuman ht[], bianma *bm, int n);
void coding(bianma *bm, int n);//译码
void coding_2(hafuman ht[], bianma *bm, int n);//译码
void output(bianma *bm, int n);
int i, j, k;

void display()
{
	printf("\n\n\n");
	printf("\t\t\t1.输出编码\n\n");
	printf("\t\t\t2.进行译码\n\n");
	printf("\t\t\t3.退出\n\n");
	printf("\t\t请选择(1~~3):  ");
}

int input(int w[], bianma *bm)
{
	int n=0;

	printf("\n请输入要进行编码的文章或句子(#结束)\n");

	while(1)
	{
		bm->data[n]=getchar();

		if(bm->data[n]=='#')
			break;
		n++;
	}

	for(i=0; i<n; i++)
	{
		w[i]=1;

		for(j=i+1; j<n; )
		{
			if( bm->data[i] == bm->data[j] )
			{
				w[i]++;

				for(k=j; k<n; k++)
				{
					bm->data[k]=bm->data[k+1];
				}
				n--; //覆盖完之后n--;
			}
			else
				j++;
		}

	}

	printf("\n\n");
	printf("不同的字符\n");
	for(i=0; i<n; i++)
	{
		printf("%c", bm->data[i]);
	}

	return n;
}

void creat_hafuman(hafuman ht[], int w[], int n)
{
	int s1, s2;
	int t;

	for(t=1; t<=n; t++)
	{
		ht[t].weight=w[t-1];
		ht[t].parent=0;
		ht[t].lchild=0;
		ht[t].rchild=0;
	}

	for(t=n+1; t<=2*n-1; t++)
	{
		ht[t].weight=0;
		ht[t].parent=0;
		ht[t].lchild=0;
		ht[t].rchild=0;
	}

	for(t=n+1; t<=2*n-1; t++)
	{
		select(ht, t-1, &s1, &s2);//前i-1中选双亲为0, 权值最小

		ht[t].weight=ht[s1].weight + ht[s2].weight;

		ht[t].lchild=s1, ht[t].rchild=s2;

		ht[s1].parent=t, ht[s2].parent=t;

	}
}

void select(hafuman ht[], int m, int *s1,  int *s2)
{
	int min1, min2, a, b;
	i=1;
	while( ht[i].parent != 0)
	{
		i++;
	}
	min1=ht[i].weight;
	a=i;

	for(j=i+1; j<=m; j++)
	{
		if(min1 > ht[j].weight && ht[j].parent==0)
		{
			min1=ht[j].weight;
			a=j;
		}

	}

	i=1;
	while( ht[i].parent != 0 || a==i )
	{
			i++;
	}

	min2=ht[i].weight;
	b=i;

	for(j=i+1; j<=m; j++)
	{
		if(j==a)
			continue;

		if(min2 > ht[j].weight && ht[j].parent==0)
		{
			min2=ht[j].weight;
			b=j;
		}
	}
	*s1=a; *s2=b;

}

void encoding(hafuman ht[], bianma *bm, int n)//编码, *copy[]为复制编码
{
	int start, c, p;
	char *ch;
	ch=(char *)malloc( n*sizeof(char) );
	ch[n-1]='\0';

	for(i=1; i<=n; i++)//n个叶子节点
	{
		start=n-1;
	    c=i, p=ht[i].parent; //p为parent, c为child

		while(p!=0)
		{
			start--;
			if(ht[p].lchild==c)
				ch[start]='0';
			else
				ch[start]='1';

			c=p; p=ht[p].parent;	//printf("\n123\n");
		}

	    strcpy( bm->copy[i-1], &ch[start] );
		//printf("\n%s\n", bm->copy[i-1]);
	}
	free(ch);

}

void coding_2(hafuman ht[], bianma *bm, int n)//译码
{
	char s[10*N];
	int p;

	printf("\n请输入要译码的字符\n");
	fflush(stdin);
	gets(s);

	printf("\n译码\n\n");
	p=2*n-1;
	for(i=0; s[i] != '\0'; i++)
	{	

		if(s[i]=='0')
			p=ht[p].lchild;

		else
			if(s[i]=='1')
			p=ht[p].rchild;	

		if(ht[p].lchild == 0 && ht[p].rchild == 0)
		{
				printf("%c", bm->data[p-1]);//p: 1~~2*n-1, bbm->data[0~~n-1]
				p=2*n-1;
				continue;
		}

	}
	puts("\n\n");
}

void output(bianma *bm, int n)
{
	printf("\n");
	for(i=0; i<n; i++)
	{
		printf("%c\t", bm->data[i] );

		printf("%s\n", bm->copy[i]);
	}
}

void main()
{
	hafuman ht[N];
	bianma *bm;
	int w[N];
	int n, m;

	bm=(bianma *)malloc( sizeof(bianma) );
	n=input(w, bm);

	printf("\n\n不同字符总数: %d\n\n", n);

    creat_hafuman(ht, w, n); 

	encoding(ht, bm, n); 

	getch();
    system("cls");

loop:	display();
	scanf("%d",  &m);
	switch(m)
	{
	case 1:
		output(bm, n);
		printf("\n\n请按任意键继续");
		getch();
		system("cls");
		goto loop;
		break;
	case 2:
		//coding(bm, n);//译码
		coding_2(ht, bm, n);//译码
		printf("\n\n请按任意键继续");
		getch();
		system("cls");
		goto loop;
		break;
	case 3:
		break;
	default:
		system("cls");
		goto loop;
	}
}