香农定理c语言程序代码,香农编码基于C语言上的实现.doc

抱歉，我不能提供文档或代码的下载链接，因为这可能侵犯版权。但是，我可以为您提供一个基于C语言的简单示例代码，用于演示如何实现香农编码。请注意，这只是一个示例代码，实际应用中可能需要进行更多的优化和改进。

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

#define MAX_SYMBOLS 256
#define MAX_CODE_LEN 256

typedef struct {
    char symbol;
    int freq;
} SymbolFreq;

typedef struct {
    int code[MAX_CODE_LEN];
    int len;
} Code;

SymbolFreq symbol_freq[MAX_SYMBOLS];
Code huffman_code[MAX_SYMBOLS];

int cmp_symbol_freq(const void *a, const void *b) {
    return ((SymbolFreq *)b)->freq - ((SymbolFreq *)a)->freq;
}

void calc_symbol_freq(char *str, int len) {
    int i;
    memset(symbol_freq, 0, sizeof(symbol_freq));
    for (i = 0; i < len; i++) {
        symbol_freq[(int)str[i]].symbol = str[i];
        symbol_freq[(int)str[i]].freq++;
    }
}

void build_huffman_tree(int num_symbols) {
    int i, j, k, l;
    int freq[MAX_SYMBOLS * 2];
    int left[MAX_SYMBOLS * 2];
    int right[MAX_SYMBOLS * 2];
    int parent[MAX_SYMBOLS * 2];
    int num_nodes = num_symbols * 2 - 1;

    for (i = 0; i < num_symbols; i++) {
        freq[i] = symbol_freq[i].freq;
        left[i] = -1;
        right[i] = -1;
        parent[i] = -1;
    }

    for (; i < num_nodes; i++) {
        freq[i] = freq[i-2] + freq[i-1];
        left[i] = i-2;
        right[i] = i-1;
        parent[i-2] = i;
        parent[i-1] = i;
    }

    for (i = num_nodes-1; i >= 0; i--) {
        if (parent[i] == -1) {
            huffman_code[(int)symbol_freq[i].symbol].len = 0;
            continue;
        }

        j = i;
        k = 0;
        while (parent[j] != -1) {
            if (left[parent[j]] == j) {
                huffman_code[(int)symbol_freq[i].symbol].code[k++] = 0;
            } else {
                huffman_code[(int)symbol_freq[i].symbol].code[k++] = 1;
            }
            j = parent[j];
        }

        huffman_code[(int)symbol_freq[i].symbol].len = k;

        for (j = 0, l = k-1; j < l; j++, l--) {
            int temp = huffman_code[(int)symbol_freq[i].symbol].code[j];
            huffman_code[(int)symbol_freq[i].symbol].code[j] = huffman_code[(int)symbol_freq[i].symbol].code[l];
            huffman_code[(int)symbol_freq[i].symbol].code[l] = temp;
        }
    }
}

void print_huffman_code(int num_symbols) {
    int i, j;
    for (i = 0; i < num_symbols; i++) {
        printf("%c: ", symbol_freq[i].symbol);
        for (j = 0; j < huffman_code[(int)symbol_freq[i].symbol].len; j++) {
            printf("%d", huffman_code[(int)symbol_freq[i].symbol].code[j]);
        }
        printf("\n");
    }
}

void encode(char *str, int len) {
    int i, j;
    for (i = 0; i < len; i++) {
        for (j = 0; j < huffman_code[(int)str[i]].len; j++) {
            printf("%d", huffman_code[(int)str[i]].code[j]);
        }
    }
    printf("\n");
}

int main(int argc, char **argv) {
    char str[1000];
    int i, len;

    printf("Enter the string to encode: ");
    fgets(str, 1000, stdin);
    len = strlen(str);
    if (len > 0 && str[len-1] == '\n') {
        str[len-1] = '\0';
        len--;
    }

    calc_symbol_freq(str, len);
    qsort(symbol_freq, MAX_SYMBOLS, sizeof(SymbolFreq), cmp_symbol_freq);
    build_huffman_tree(len);
    print_huffman_code(len);
    encode(str, len);

    return 0;
}