用c语言编程：已知通信员甲要传输一串电文，WINNIE WILL WIN，请设计电文编码并使译码唯一，要求写出C语言代码

可以使用哈夫曼编码实现电文编码和译码的唯一性。具体实现步骤如下：

1. 统计电文中每个字符出现的次数，并将其存入一个数组中。

2. 根据字符出现次数构建哈夫曼树。

3. 对哈夫曼树进行遍历，赋予每个字符对应的编码。

4. 将编码后的电文输出，并将其存入文件中。

5. 对编码后的电文进行译码。

6. 将译码后的电文输出，并将其存入文件中。

下面是一份示例代码：

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

#define MAX_CHARACTERS 256

// 哈夫曼树节点
typedef struct node {
    char character;
    int frequency;
    struct node *left;
    struct node *right;
} Node;

// 哈夫曼编码
typedef struct code {
    char character;
    char *bits;
} Code;

// 哈夫曼树队列
typedef struct queue {
    Node *node;
    struct queue *next;
} Queue;

// 统计字符出现次数
void count_characters(char *text, int *frequencies) {
    int i;
    for (i = 0; i < strlen(text); i++) {
        frequencies[(int) text[i]]++;
    }
}

// 创建哈夫曼树节点
Node *create_node(char character, int frequency) {
    Node *node = (Node *) malloc(sizeof(Node));
    node->character = character;
    node->frequency = frequency;
    node->left = NULL;
    node->right = NULL;
    return node;
}

// 创建哈夫曼树队列节点
Queue *create_queue_node(Node *node) {
    Queue *queue_node = (Queue *) malloc(sizeof(Queue));
    queue_node->node = node;
    queue_node->next = NULL;
    return queue_node;
}

// 插入哈夫曼树队列节点
Queue *insert_queue_node(Queue *head, Queue *queue_node) {
    if (head == NULL) {
        head = queue_node;
    } else {
        Queue *current = head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = queue_node;
    }
    return head;
}

// 弹出哈夫曼树队列节点
Queue *pop_queue_node(Queue *head) {
    if (head == NULL) {
        return NULL;
    } else {
        Queue *temp = head;
        head = head->next;
        temp->next = NULL;
        return temp;
    }
}

// 创建哈夫曼树
Node *create_huffman_tree(int *frequencies) {
    Queue *queue = NULL;
    int i;
    for (i = 0; i < MAX_CHARACTERS; i++) {
        if (frequencies[i] > 0) {
            Node *node = create_node(i, frequencies[i]);
            queue = insert_queue_node(queue, create_queue_node(node));
        }
    }
    while (queue != NULL && queue->next != NULL) {
        Queue *first = pop_queue_node(queue);
        Queue *second = pop_queue_node(queue);
        Node *node = create_node('\0', first->node->frequency + second->node->frequency);
        node->left = first->node;
        node->right = second->node;
        queue = insert_queue_node(queue, create_queue_node(node));
        free(first);
        free(second);
    }
    Node *root = NULL;
    if (queue != NULL) {
        root = queue->node;
        free(queue);
    }
    return root;
}

// 遍历哈夫曼树赋予编码
void traverse_tree(Node *node, char *bits, int depth, Code *codes) {
    if (node == NULL) {
        return;
    }
    if (node->left == NULL && node->right == NULL) {
        int i;
        for (i = 0; i < MAX_CHARACTERS; i++) {
            if (node->character == i) {
                Code code = {i, (char *) malloc(sizeof(char) * (depth + 1))};
                strncpy(code.bits, bits, depth);
                code.bits[depth] = '\0';
                codes[i] = code;
                return;
            }
        }
    }
    bits[depth] = '0';
    traverse_tree(node->left, bits, depth + 1, codes);
    bits[depth] = '1';
    traverse_tree(node->right, bits, depth + 1, codes);
}

// 哈夫曼编码
void huffman_encode(char *text, Code *codes) {
    int frequencies[MAX_CHARACTERS] = {0};
    count_characters(text, frequencies);
    Node *root = create_huffman_tree(frequencies);
    char bits[MAX_CHARACTERS] = {'\0'};
    traverse_tree(root, bits, 0, codes);
    int i;
    for (i = 0; i < strlen(text); i++) {
        printf("%s", codes[(int) text[i]].bits);
    }
}

// 哈夫曼译码
void huffman_decode(char *text, Node *root) {
    Node *current = root;
    int i;
    for (i = 0; i < strlen(text); i++) {
        if (text[i] == '0') {
            current = current->left;
        } else {
            current = current->right;
        }
        if (current->left == NULL && current->right == NULL) {
            printf("%c", current->character);
            current = root;
        }
    }
}

int main() {
    char text[] = "WINNIE WILL WIN";
    Code codes[MAX_CHARACTERS];
    huffman_encode(text, codes);
    Node *root = create_huffman_tree(NULL);
    char bits[MAX_CHARACTERS] = {'\0'};
    traverse_tree(root, bits, 0, codes);
    printf("\n");
    huffman_decode("0010110010111100001110011101100110000010101111100111001011111", root);
    printf("\n");
    return 0;
}