哈弗曼编法c语言怎么编

Huffman编码是一种基于字符出现频率进行数据压缩的算法，它可以将原始数据中出现频率较高的字符用较短的二进制编码表示，从而达到压缩数据的目的。

下面是一个用C语言实现Huffman编码的示例代码：

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

#define MAX_NODE 256

typedef struct huffman_node {
    int weight;
    int parent;
    int left_child;
    int right_child;
} huffman_node;

void huffman_build(huffman_node *node, int n)
{
    int i, j, m1, m2, x1, x2;

    for (i = 0; i < 2 * n - 1; i++) {
        node[i].weight = 0;
        node[i].parent = -1;
        node[i].left_child = -1;
        node[i].right_child = -1;
    }

    for (i = 0; i < n; i++) {
        printf("Enter weight of node %d: ", i);
        scanf("%d", &node[i].weight);
    }

    for (i = 0; i < n - 1; i++) {
        m1 = m2 = 0x7fffffff;
        x1 = x2 = 0;

        for (j = 0; j < n + i; j++) {
            if (node[j].parent == -1 && node[j].weight < m1) {
                m2 = m1;
                x2 = x1;
                m1 = node[j].weight;
                x1 = j;
            } else if (node[j].parent == -1 && node[j].weight < m2) {
                m2 = node[j].weight;
                x2 = j;
            }
        }

        node[x1].parent = n + i;
        node[x2].parent = n + i;
        node[n + i].weight = node[x1].weight + node[x2].weight;
        node[n + i].left_child = x1;
        node[n + i].right_child = x2;
    }
}

void huffman_encode(huffman_node *node, int n, char *str)
{
    int i, j, k, p;
    char *code[MAX_NODE];

    for (i = 0; i < MAX_NODE; i++) {
        code[i] = (char *) malloc(n * sizeof(char));
    }

    code[n - 1][0] = '\0';

    for (i = n - 2; i >= 0; i--) {
        j = node[i].left_child;
        k = node[i].right_child;

        strcpy(code[j], code[i]);
        strcat(code[j], "0");

        strcpy(code[k], code[i]);
        strcat(code[k], "1");
    }

    printf("Huffman codes:\n");

    for (i = 0; i < n; i++) {
        printf("Node %d: %s\n", i, code[i]);
    }

    printf("Encoded string: ");

    for (i = 0; i < strlen(str); i++) {
        p = str[i];
        printf("%s", code[p]);
    }

    printf("\n");

    for (i = 0; i < MAX_NODE; i++) {
        free(code[i]);
    }
}

int main()
{
    int n;
    char str[100];
    huffman_node node[MAX_NODE];

    printf("Enter the number of nodes: ");
    scanf("%d", &n);

    printf("Enter the string to be encoded: ");
    scanf("%s", str);

    huffman_build(node, n);
    huffman_encode(node, n, str);

    return 0;
}

以上代码实现了简单的Huffman编码，输入字符的出现频率，然后对字符进行编码，输出编码后的字符串。当然，Huffman编码还可以进行更多的优化，比如使用最小堆来进行节点的选择，这样可以更快速地找到出现频率较小的节点，从而提高编码效率。