"Data structure" Huffman Tree Implementation coding decoding

A Huffman tree is generated based on the number of characters in a string as the weight of the character.

Then according to the generated Huffman code, the arbitrary string Implementation code, the arbitrary binary string implementation decoding.

Program Run Result:

1. Program Main interface:

2. Create Huffman tree and encodings based on the string:

3. The resulting encoding table is as follows:

4. Encode the string according to the generated Huffman code:

5. The generated encoding is saved in the file:

6. Decoding the binary string:

Results:

Code:

Huffman Tree generation and coding of common, as well as encoding and decoding functions

_huffmantree_h#ifndef _huffmantree_h#define _huffmantree_htypedef struct {   unsigned int weight;   char ch;   unsigned int parent,lchild,rchild;} Htnode,*huffmantree;  typedef char **huffmancode; These three are Huffman tree generation int min1 (huffmantree t,int i);     Select the smallest of the weights array, void Select (Huffmantree t,int i,int *s1,int *s2);   The smallest of the two weights in the array, and change the temporary array corresponding position to 1 to prevent the repetition of the selection void huffmancoding (Huffmantree *ht,huffmancode *hc,int *w,int N);  According to the weights array w, and the number of elements n to open up space, HC storage code void getweightinfile (int *w);//read letters from MyTxt.TXT, use the number of letters as weights, generate an array and return void Bianmainfile ( Huffmantree *p,huffmancode CD);    According to the encoded. txt inside letter, find the corresponding subscript, in HC inside matching code void Yimainfile (Huffmantree *p);   The  root node of the analysis of the number of the subscript should be 2n-1 ... So just follow the code 0 1 to determine left or right end until = encounter meaningful letter stop #endif  //

Read and write to the specified file

Myfile.h#ifndef _myfile_h#define _myfile_h#define My_strmax 100void changmytxtfile (); void Showmytxtfile (); void Showbianmafile (); void Showyimafile (); void Changbianmafile (); #endif   //myfile.h

Huffmantree.c#include <stdio.h> #include <stdlib.h> #include <string.h> #include "HuffmanTree.h" int min1 (Huffmantree t,int i) {/* Returns the root node ordinal of the tree with the lowest weight in the I node, the function Select () calls */int j,flag;unsigned int k=10000000;/* takes K to be no less than possible (no character Number integer maximum) */for (j=1;j<=i;j++) if (t[j].weight<k&&t[j].parent==0)//T[j] is the root node of the tree */k=t[j].weight,flag=j;t[ Flag].parent=1; /* Assign 1 to the parent of the selected root node to avoid finding the node */return flag for the 2nd time; }void Select (Huffmantree t,int i,int *s1,int *s2) {/* Selects the root node ordinal of the tree with the least 2 weights in the I node, S1 the one with the smaller sequence number, */int j;*s1=min1 (t,i); *s2=min1 (t,i); if (*s1>*s2) {j=*s1;*s1=*s2;*s2=j;}} void Huffmancoding (Huffmantree *ht,huffmancode *hc,int *w,int N)/* Algorithm 6.12 */{/w holds weights of n characters (all >0), constructs Huffman Tree HT, and find the n characters of Huffman encoded HC */int m,i,s1,s2,start,num=0;unsigned c,f;    Huffmantree P;char *cd;if (n<=1) return;m=2*n-1; The space opened up is more than the number of elements because the subsequent generation of new subtrees is used to *ht= (Huffmantree) malloc ((m+1) *sizeof (Htnode)); /* Unit No. 0 is not used */for (p=*ht+1,i=1;i<=n;++i,++p,++w,++num) {(*p). weight=*w;//This section is assigned to the defined subtree, including the letter A-Z weights from the array to derive if (i<26) ( *P). Ch=97+num;else If(i==26) {(*p). Ch=97+num;num=-1;} else if (i<=52&&i>26) (*p). Ch=65+num;else if (i==53) (*p). Ch=32;else if (i==54) (*p). ch= ' \ n ';(*p). parent= 0; (*p). Lchild=0; (*p). Rchild=0;} for (; i<=m;++i,++p) (*p). Parent=0;for (I=n+1;i<=m;++i)//Kenkheffman tree */{/* in ht[1~i-1] Select two nodes with a parent of 0 and a minimum of weight,     The serial numbers are S1 and S2 */select (*HT,I-1,&AMP;S1,&AMP;S2);(*ht) [S1].parent= (*HT)] [s2].parent=i;                        This section gives the new node initial value (*HT) [I].lchild=s1; (*HT) [I].rchild=s2; (*HT)] [i].ch= '! ';   They're storing it! So you can tell if this node makes sense (*HT) [I].weight= (*HT) [s1].weight+ (*HT) [S2].weight;} Huffman codes are saved in HC (two-dimensional array)/* Huffman encoding */*hc= (Huffmancode) malloc ((n+1) *sizeof (char*)) for each character from the leaf to the root, and/* assigns a N-character encoded head-pointer vector ([0] NO) */cd= (char*) malloc (n*sizeof (char)); /* Allocate a working space for coding */cd[n-1]= ' + '; /* Encoding Terminator */for (i=1;i<=n;i++) {/* character Fu Tiuhe */start=n-1;/* encoding Terminator position */for (c=i,f= (*HT) [i].parent;f!=0;c=f,f= (*HT) [F] . Parent)/* from leaf to root reverse coding */if ((*HT) [f].lchild==c) cd[--start]= ' 0 '; elsecd[--start]= ' 1 ';(*hc) [i]= (char*) malloc (( N-start) *sizeof (char));/* Allocates space for the I-character encoding */strCPY ((*HC) [I],&cd[start]); /* Copy the Encoding (string) from the CD to the HC */}free (CD); /* Free workspace */}void getweightinfile (int *w) {file *pfr;int I=0;PFR = fopen ("Record Information \\mytxt.txt", "R");//Read file if (pfr==null) {p rintf ("File operation failed"); return;} Else{while (!feof (PFR))//until the file is read, read one line at a time {char str[256] = {0};fgets (str, n, PFR);//read one line I=0;while (str[i]!=0)//if this is a letter, then the corresponding array from 0-25 found a corresponding value Gaga implementation of the number of letters in the calculation file {if (str[i]<= ' z ' && str[i]>= ' a ')//97-122 65-90 32w[str[i] -97]++;if (str[i]<= ' Z ' && str[i]>= ' A ') w[str[i]-65+26]++;if (str[i]== ") w[26*2]++;if (str[i]== ' \ n ') w[ 26*2+1]++;i++;}}}                    Fclose (PFR);} File runs out to close void Bianmainfile (Huffmantree *p,huffmancode cd) {file *PFR; File *pfw;//huffmantree ptr= (*p) +1;int i;int num;int COUNT=1;PFR = fopen ("Record Information \\mytxt.txt", "R");//Read files PFW = fopen ("Log information \ \ encoded. txt "," w ");//write file if (Pfr==null | | pfw==null) {printf (" File operation failed "); return;} else {while (!feof (PFR)) {char str[256] = {0};fgets (str, n, PFR);//reads a row of I=0;num=-1;while (str[i]!=0) {if (str[i]<=122 &&amp str[i]>=97)//1-26num=str[i]-96;else if (str[i]<=90 && str[i]>=65)//27-52num=str[i]-64+26;else if (s TR[I]==32) Num=53;else if (str[i]== ' \ n ') num=54;if (num!=-1)//The Code inside the CD is output to the encoded. txt {if (count==1) count++;else//fputs ( Cd[num], PFW); fprintf (PFW, "%s\n", Cd[num]);} I++;num=-1;}} Fclose (PFR); fclose (PFW);}} void Yimainfile (Huffmantree *p) {FILE *PFR;  FILE *pfw;char S[2]={0};int i=0,num=107; 51=2*26-1 2*54-1int N;PFR = fopen ("Record information \ \ encoded. txt", "R");//Read File PFW = fopen ("Record information \ \ decode. txt", "w");//write file if (Pfr==null | | p Fw==null) {printf ("File operation failed"); return;} else {while (!feof (PFR)) {char str[255] = {0};fgets (str, 255, PFR); i=0;//reads one line num=107;while (str[i]!=0) {n=i;while (Str[i]            !=0) {if ((*p) [num].ch!= '! ') If found left and right move found the letter immediately exit match next break;if (str[i]== ' 0 ')//0 Left 1 R num= (*p) [Num].lchild;else if (str[i]== ' 1 ') num= (*p) [n um].rchild;i++;} if ((*p) [num].ch== '! ' && str[i]!= ') printf ("Because the encoding is not complete,%d-%d code is dropped \ n", n+1,i); else if (str[i]!= '} ') {s[0]= (*p) [Num].ch;fputs (S, PFW);} num=107;}}} Fclose (PFR); fclose (PFW);}

Myfile.c#include <stdlib.h> #include <stdio.h> #include "myfile.h" #include <conio.h>void Changmytxtfile () {file *pfw;int s;int num=1;pfw=fopen ("Record Information \\mytxt.txt", "w"), if (pfw==null) {printf ("File operation failed"); return ;} while (S=getchar (), s!=-1) {fprintf (PFW, "%c", s);} Fclose (PFW);} void Showmytxtfile () {file *pfr;pfr=fopen ("Record Information \\mytxt.txt", "R"), if (pfr==null) {printf ("File operation failed"), return;          else {while (!feof (PFR)) {char str[256] = {0};fgets (str, n, PFR); Dynamically traverse file puts (str);}} Fclose (PFR);} void Showbianmafile () {file *pfr;pfr=fopen ("record information \ \ encoded. txt", "R"), if (pfr==null) {printf ("File operation failed"), return; else {while (!feof (PFR)) {char str[256] = {0};fgets (str, n, PFR);p UTS (str);}} Fclose (PFR);} void Showyimafile () {file *pfr;pfr=fopen ("record information \ \ decode. txt", "R"), if (pfr==null) {printf ("File operation failed"); return;} else {while (!feof (PFR)) {char str[256] = {0};fgets (str, n, PFR);p UTS (str);}} Fclose (PFR);} void Changbianmafile () {file *pfw;int s;pfw=fopen ("record information \ \ encoded. txt", "w"), if (pfw==null) {printf ("Record information \ \ File operation failed");while (S=getchar (), s!=-1) {fprintf (PFW, "%c", s);} Fclose (PFW);}

Main.c#include <stdlib. H> #include <stdio.   h> #include "HuffmanTree.h" #include "myfile.h" #define Myhfmnum 26*2+2int Main () {Huffmantree HT;   Huffmancode HC;   int w[myhfmnum]={0},n=myhfmnum,i;   Char s[my_strmax]={0};    int Num;system ("color 3e");   Change the color Menu:system ("CLS");   Puts ("***********************************************");   Puts ("1. Create a new Code");   Puts ("2. Code");   Puts ("3. Decoding");   Puts ("4. Exit");   Puts ("***********************************************");       Puts ("Enter the desired action:");   scanf ("%d", &num);   Switch (num) {Case 1: {FILE *pfw; System ("CLS");   Each operation cleans up the screen puts ("Enter a string that accumulates weights based on the number of characters, resulting in a tree");   Changmytxtfile ();   Getweightinfile (w);   Huffmancoding (&ht,&hc,w,n);   Pfw=fopen ("record information \ \ Code table. txt", "w");   if (pfw==null) {printf ("File operation failed"); return 0;}     fprintf (PFW, "coded letter weights \ n"); for (i=1;i<=n;i++)//Put the generated encoding table in the file for easy comparison with {fprintf (PFW, "%10s\t%c\t%2d\n", Hc[i],ht[i].ch,ht[i].weight      ); } fclose (PFW); System ("PauSe ");   Goto MENU;   } Case 2: {System ("CLS");   Puts ("Enter the string to encode");   Changmytxtfile ();    Bianmainfile (&AMP;HT,HC);   Showbianmafile ();   System ("pause");   Goto MENU;   } Case 3:{system ("CLS");   Puts ("Input binary number to decode");   Changbianmafile ();   Yimainfile (&AMP;HT);    Showyimafile (); System ("pause");   Pause for a moment equivalent to Getch goto MENU;   } case 4:return 0; Default:puts ("Wrong input!");              System ("pause"); goto MENU; } return 0;}

"Data structure" Huffman Tree Implementation coding decoding