在这里插入代码片#include <stdio.h>
#include <stdlib.h> //为exit()提供原型
#include <string.h>
//哈夫曼树结点的结构
typedef struct {
char ch; //该字符域用于存放节点的关键字
int weight;
int parent, lchild, rchild;
}HTNode, * HuffmanTree; //动态分配数组存储哈夫曼树
typedef char** HuffmanCode; //动态分配数组存储哈夫曼编码表
void Menu(); //显示菜单
void HuffmanCoding(HuffmanTree& HT, char* character, int* w, int n); //建立哈夫曼树
void select(HuffmanTree HT, int j, int* x, int* y); //从已建好的哈夫曼树中选择parent为0，weight最小的两个结点
void Init();
void Coding(); //编码
void Decoding(); //译码
void Print_code(); //打印译码好的代码
void Print_tree(); //打印哈夫曼树
int Read_tree(HuffmanTree&); //从文件中读入哈夫曼树
void find(HuffmanTree& HT, char* code, char* text, int i, int m); //译码时根据01字符串寻找相应叶子节点的递归算法
void Convert_tree(unsigned char T[100][100], int s, int* i, int j); //将内存中的哈夫曼树转换成凹凸表形式的赫夫曼树
HuffmanTree HT; //全局变量
int n = 0; //全局变量，存放赫夫曼树叶子结点的数目
int main()
{
char select;
while (1)
{
Menu();
scanf("%c", &select);
switch (select) //选择操作，根据不同的序号选择不同的操作
{
case '1':Init();
break;
case '2':Coding();
break;
case '3':Decoding();
break;
case '4':Print_code();
break;
case '5':Print_tree();
break;
case '0':exit(1);
default:printf("Input error!\n");
}
getchar();
}
return 0;
}
void Menu() //操作选择界面
{
printf(" -----------------------------------------------------\n");
printf(" -- 请选择操作 --\n");
printf(" -----------------------------------------------------\n");
printf(" \n");
printf(" ---------------------1初始化哈夫曼树 ---------------\n");
printf(" ---------------------2编码 ---------------\n");
printf(" ---------------------3译码 ---------------\n");
printf(" ---------------------4打印代码文件 ---------------\n");
printf(" ---------------------5打印哈夫曼树 ---------------\n");
printf(" ---------------------0退出 ---------------\n");
printf(" -----------------------------------------------------\n");
}
//初始化函数，输入n个字符及其对应的权值，根据权值建立哈夫曼树，并将其存于文件hfmtree中
void Init()
{
FILE* fp;
int i, n, w[52]; //数组存放字符的权值
char character[52]; //存放n个字符
printf("\n输入字符个数 n:");
scanf("%d", &n); //输入字符集大小
printf("输入%d个字符及其对应的权值:\n", n);
for (i = 0; i < n; i++)
{
char b = getchar();
scanf("%c", &character[i]);
scanf("%d", &w[i]); //输入n个字符和对应的权值
}
HuffmanCoding(HT, character, w, n); //建立赫夫曼树
if ((fp = fopen("D:\\hfmtree.txt", "w")) == NULL)
printf("Open file hfmtree.txt error!\n");
for (i = 1; i <= 2 * n - 1; i++)
{
if (fwrite(&HT[i], sizeof(HTNode), 1, fp) != 1) //将建立的赫夫曼树存入文件hfmtree.txt中
printf("File write error!\n");
}
printf("\n赫夫曼树建立成功，并已存于文件hfmtree.txt中\n");
fclose(fp);
}
//构造哈夫曼树的算法
void HuffmanCoding(HuffmanTree& HT, char* character, int* w, int n)
{ //w存放n个字符的权值（均>0），构造哈夫曼树HT
int m, i, x, y;
HuffmanTree p;
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, ++character, ++w)
{
p->ch = *character; p->weight = *w; p->parent = 0; p->lchild = 0; p->rchild = 0;
}
for (; i <= m; ++i, ++p) { p->ch = 0; p->weight = 0; p->parent = 0; p->lchild = 0; p->rchild = 0; }
for (i = n + 1; i <= m; ++i)
{
select(HT, i - 1, &x, &y);
HT[x].parent = i; HT[y].parent = i;
HT[i].lchild = x; HT[i].rchild = y;
HT[i].weight = HT[x].weight + HT[y].weight;
}
}
//从HT[1]到HT[j]中选择parent为0，weight最小的两个结点，用x和y返回其序号
void select(HuffmanTree HT, int j, int* x, int* y)
{
int i;
//查找weight最小的结点
for (i = 1; i <= j; i++)
if (HT[i].parent == 0)
{
*x = i; break;
}
for (; i <= j; i++)
if ((HT[i].parent == 0) && (HT[i].weight < HT[*x].weight))
*x = i;
HT[*x].parent = 1;
//查找weight次小的结点
for (i = 1; i <= j; i++)
if (HT[i].parent == 0)
{
*y = i; break;
}
for (; i <= j; i++)
if ((HT[i].parent == 0) && (i != *x) && (HT[i].weight < HT[*y].weight))
*y = i;
}
//对文件tobetrans中的正文进行编码，然后将结果存入文件codefile中
void Coding()
{
FILE* fp, * fw;
int i, f, c, start;
char* cd;
HuffmanCode HC;
if (n == 0)
n = Read_tree(HT);//从文件hfmtree.txt中读入赫夫曼树,返回叶子结点数
//求赫夫曼树中各叶子节点的字符对应的的编码，并存于HC指向的空间中
{
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);
}
if ((fp = fopen("D:\\tobetrans.txt", "rb")) == NULL)
printf("Open file tobetrans.txt error!\n");
if ((fw = fopen("D:\\codefile.txt", "wb+")) == NULL)
printf("Open file codefile.txt error!\n");
char temp;
fscanf(fp, "%c", &temp); //从文件读入第一个字符
while (!feof(fp))
{
for (i = 1; i <= n; i++)
if (HT[i].ch == temp) break; //在赫夫曼树中查找字符所在的位置
for (int r = 0; HC[i][r] != '\0'; r++) //将字符对应的编码存入文件
fputc(HC[i][r], fw);
fscanf(fp, "%c", &temp); //从文件读入下一个字符
}
fclose(fw);
fclose(fp);
printf("\n已将文件hfmtree.txt成功编码,并已存入codefile.txt中！\n\n");
}
//将文件codefile中的代码进行译码，结果存入文件textfile中
void Decoding()
{
FILE* fp, * fw;
int m, i;
char* code, * text, * p;
if (n == 0)
n = Read_tree(HT);//从文件hfmtree.txt中读入赫夫曼树,返回叶子结点数
if ((fp = fopen("D:\\codefile.txt", "rb")) == NULL)
printf("Open file codefile.txt error!\n");
if ((fw = fopen("D:\\textfile.txt", "wb+")) == NULL)
printf("Open file textfile.txt error!\n");
code = (char*)malloc(sizeof(char));
fscanf(fp, "%c", code); //从文件读入一个字符
for (i = 1; !feof(fp); i++)
{
code = (char*)realloc(code, (i + 1) * sizeof(char)); //增加空间
fscanf(fp, "%c", &code[i]); //从文件读入下一个字符
}
code[i - 1] = '\0';
// codefile.txt文件中的字符已全部读入，存放在code数组中
text = (char*)malloc(100 * sizeof(char));
p = text;
m = 2 * n - 1;
if (*code == '0')
find(HT, code, text, HT[m].lchild, m); //从根节点的左子树去找
else
find(HT, code, text, HT[m].rchild, m); //从根节点的右子树去找
for (i = 0; p[i] != '\0'; i++) //把译码好的字符存入文件textfile.txt中
fputc(p[i], fw);
fclose(fp);
fclose(fw);
printf("\n已将codefile.txt文件成功译码，并已存入textfile.txt文件！\n\n");
}
//将文件codefi1e以紧凑格式显示在终端上,每行50个代码。同时将此字符形式的编码文件写入文件codeprint中。
void Print_code()
{
FILE* fp, * fw;
char temp;
int i;
if ((fp = fopen("D:\\codefile.txt", "rb")) == NULL)
printf("Open file codefile.txt error!\n");
if ((fw = fopen("D:\\codeprint.txt", "wb+")) == NULL)
printf("Open file codeprint.txt error!\n");
printf("\n文件codefi1e显示如下:\n");
fscanf(fp, "%c", &temp); //从文件读入一个字符
for (i = 1; !feof(fp); i++)
{
printf("%c", temp);
if (i % 50 == 0) printf("\n");
fputc(temp, fw); //将该字符存入文件codeprint.txt中
fscanf(fp, "%c", &temp); //从文件读入一个字符
}
printf("\n\n已将此字符形式的编码写入文件codeprint.txt中！\n\n");
fclose(fp);
fclose(fw);
}
//将已在内存中的哈夫曼树显示在屏幕上，并将此字符形式的哈夫曼树写入文件treeprint中。
void Print_tree()
{
unsigned char T[100][100];
int i, j, m = 0;
FILE* fp;
if (n == 0)
n = Read_tree(HT); //从文件hfmtree.txt中读入赫夫曼树,返回叶子结点数
Convert_tree(T, 0, &m, 2 * n - 1); //将内存中的赫夫曼树转换成凹凸表形式的树，存于数组T中
if ((fp = fopen("D:\\treeprint.txt", "wb+")) == NULL)
printf("Open file treeprint.txt error!\n");
printf("\n打印已建好的赫夫曼树：\n");
for (i = 1; i <= 2 * n - 1; i++)
{
for (j = 0; T[i][j] != 0; j++)
{
if (T[i][j] == ' ') { printf(" "); fputc(T[i][j], fp); }
else
{
printf("%d", T[i][j]); fprintf(fp, "%d\n", T[i][j]);
}
}
printf("\n");
}
fclose(fp);
printf("\n已将该字符形式的哈夫曼树写入文件treeprint.txt中！\n\n");
}
//从文件hfmtree.txt中读入赫夫曼树，返回叶子节点数
int Read_tree(HuffmanTree& HT)
{
FILE* fp;
int i, n;
HT = (HuffmanTree)malloc(sizeof(HTNode));
if ((fp = fopen("D:\\hfmtree.txt", "r")) == NULL)
printf("Open file hfmtree.txt error!\n");
for (i = 1; !feof(fp); i++)
{
HT = (HuffmanTree)realloc(HT, (i + 1) * sizeof(HTNode)); //增加空间
fread(&HT[i], sizeof(HTNode), 1, fp); //读入一个节点信息
}
fclose(fp);
n = (i - 1) / 2;
return n;
}
//译码时根据01字符串寻找相应叶子节点的递归算法
void find(HuffmanTree& HT, char* code, char* text, int i, int m)
{
if (*code != '\0') //若译码未结束
{
code++;
if (HT[i].lchild == 0 && HT[i].rchild == 0) //若找到叶子节点
{
*text = HT[i].ch; //将叶子节点的字符存入text中
text++;
if ((*code == '0'))
find(HT, code, text, HT[m].lchild, m); //从根节点的左子树找
else
find(HT, code, text, HT[m].rchild, m); //从根节点的右子树找
}
else //如果不是叶子节点
if (*code == '0')
find(HT, code, text, HT[i].lchild, m); //从该节点的左子树去找
else
find(HT, code, text, HT[i].rchild, m); //从该节点的右子树去找
}
else
*text = '\0'; //译码结束
}
//将文件中的赫夫曼树转换成凹凸表形式的赫夫曼树打印出来
void Convert_tree(unsigned char T[100][100], int s, int* i, int j)
{
int k, l;
l = ++(*i);
for (k = 0; k < s; k++)
T[l][k] = ' ';
T[l][k] = HT[j].weight;
if (HT[j].lchild)
Convert_tree(T, s + 1, i, HT[j].lchild);
if (HT[j].rchild)
Convert_tree(T, s + 1, i, HT[j].rchild);
T[l][++k] = '\0';
}