使用C语言编写一段程序 根据A-Z、空格、逗号、句号的频率确定哈夫曼树，并使用哈夫曼树对文本解码

下面是用C语言实现的哈夫曼编码和解码程序。

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

#define MAX_LEN 1000
#define MAX_NODES 1000

typedef struct Node {
    char data;
    int weight;
    int lchild, rchild, parent;
    char code[MAX_LEN];
} Node;

void createHuffmanTree(Node *nodes, int n) {
    int i, j, p1, p2, min1, min2;
    for (i = 0; i < 2 * n - 1; i++) {
        nodes[i].weight = 0;
        nodes[i].lchild = -1;
        nodes[i].rchild = -1;
        nodes[i].parent = -1;
    }
    for (i = 0; i < n; i++) {
        printf("Enter the character and its weight: ");
        fflush(stdout);
        scanf(" %c %d", &nodes[i].data, &nodes[i].weight);
    }
    for (i = 0; i < n - 1; i++) {
        min1 = min2 = MAX_NODES;
        p1 = p2 = -1;
        for (j = 0; j < n + i; j++) {
            if (nodes[j].parent == -1) {
                if (nodes[j].weight < min1) {
                    min2 = min1;
                    p2 = p1;
                    min1 = nodes[j].weight;
                    p1 = j;
                } else if (nodes[j].weight < min2) {
                    min2 = nodes[j].weight;
                    p2 = j;
                }
            }
        }
        nodes[p1].parent = n + i;
        nodes[p2].parent = n + i;
        nodes[n + i].weight = nodes[p1].weight + nodes[p2].weight;
        nodes[n + i].lchild = p1;
        nodes[n + i].rchild = p2;
    }
}

void encode(Node *nodes, int n) {
    int i, j, k;
    for (i = 0; i < n; i++) {
        k = i;
        while (nodes[k].parent != -1) {
            j = k;
            k = nodes[k].parent;
            if (nodes[k].lchild == j) {
                strcat(nodes[i].code, "0");
            } else {
                strcat(nodes[i].code, "1");
            }
        }
        strrev(nodes[i].code);
    }
}

void decode(Node *nodes, int n) {
    char str[MAX_LEN];
    printf("Enter the encoded string: ");
    fflush(stdout);
    scanf("%s", str);
    int i, j, k;
    for (i = 0; i < strlen(str); i++) {
        k = n + n - 2;
        while (nodes[k].lchild != -1) {
            if (str[i] == '0') {
                k = nodes[k].lchild;
            } else {
                k = nodes[k].rchild;
            }
            i++;
        }
        printf("%c", nodes[k].data);
        i--;
    }
}

int main() {
    Node nodes[MAX_NODES];
    int n;
    printf("Enter the number of characters: ");
    fflush(stdout);
    scanf("%d", &n);
    createHuffmanTree(nodes, n);
    encode(nodes, n);
    for (int i = 0; i < n; i++) {
        printf("%c: %s\n", nodes[i].data, nodes[i].code);
    }
    decode(nodes, n);
    return 0;
}

这个程序首先让用户输入字符和它们的权重，然后根据它们的权重创建哈夫曼树。接下来，它使用哈夫曼树对每个字符进行编码，并打印编码结果。最后，它让用户输入一个编码的字符串，并使用哈夫曼树将其解码为原始字符串。