用c++写一个哈夫曼编码解码的程序

以下是使用C语言实现哈夫曼编码解码的示例代码：

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

#define MAX_TREE_HT 100

// 结构体定义
struct MinHeapNode {
    char data;
    unsigned freq;
    struct MinHeapNode *left, *right;
};

struct MinHeap {
    unsigned size;
    unsigned capacity;
    struct MinHeapNode** array;
};

struct MinHeapNode* newNode(char data, unsigned freq) {
    struct MinHeapNode* temp
        = (struct MinHeapNode*)malloc(sizeof(struct MinHeapNode));
    temp->left = temp->right = NULL;
    temp->data = data;
    temp->freq = freq;
    return temp;
}

struct MinHeap* createMinHeap(unsigned capacity) {
    struct MinHeap* minHeap
        = (struct MinHeap*)malloc(sizeof(struct MinHeap));
    minHeap->size = 0;
    minHeap->capacity = capacity;
    minHeap->array
        = (struct MinHeapNode**)malloc(minHeap->capacity * sizeof(struct MinHeapNode*));
    return minHeap;
}

void swapMinHeapNode(struct MinHeapNode** a, struct MinHeapNode** b) {
    struct MinHeapNode* t = *a;
    *a = *b;
    *b = t;
}

void minHeapify(struct MinHeap* minHeap, int idx) {
    int smallest = idx;
    int left = 2 * idx + 1;
    int right = 2 * idx + 2;
    if (left < minHeap->size
        && minHeap->array[left]->freq < minHeap->array[smallest]->freq)
        smallest = left;
    if (right < minHeap->size
        && minHeap->array[right]->freq < minHeap->array[smallest]->freq)
        smallest = right;
    if (smallest != idx) {
        swapMinHeapNode(&minHeap->array[smallest], &minHeap->array[idx]);
        minHeapify(minHeap, smallest);
    }
}

int isSizeOne(struct MinHeap* minHeap) {
    return (minHeap->size == 1);
}

struct MinHeapNode* extractMin(struct MinHeap* minHeap) {
    struct MinHeapNode* temp = minHeap->array[0];
    minHeap->array[0] = minHeap->array[minHeap->size - 1];
    --minHeap->size;
    minHeapify(minHeap, 0);
    return temp;
}

void insertMinHeap(struct MinHeap* minHeap, struct MinHeapNode* minHeapNode) {
    ++minHeap->size;
    int i = minHeap->size - 1;
    while (i
           && minHeapNode->freq < minHeap->array[(i - 1) / 2]->freq) {
        minHeap->array[i] = minHeap->array[(i - 1) / 2];
        i = (i - 1) / 2;
    }
    minHeap->array[i] = minHeapNode;
}

void buildMinHeap(struct MinHeap* minHeap) {
    int n = minHeap->size - 1;
    int i;
    for (i = (n - 1) / 2; i >= 0; --i)
        minHeapify(minHeap, i);
}

void printArr(int arr[], int n) {
    int i;
    for (i = 0; i < n; ++i)
        printf("%d", arr[i]);
    printf("\n");
}

int isLeaf(struct MinHeapNode* root) {
    return !(root->left) && !(root->right);
}

struct MinHeap* createAndBuildMinHeap(char data[], int freq[], int size) {
    struct MinHeap* minHeap = createMinHeap(size);
    for (int i = 0; i < size; ++i)
        minHeap->array[i] = newNode(data[i], freq[i]);
    minHeap->size = size;
    buildMinHeap(minHeap);
    return minHeap;
}

struct MinHeapNode* buildHuffmanTree(char data[], int freq[], int size) {
    struct MinHeapNode *left, *right, *top;
    struct MinHeap* minHeap = createAndBuildMinHeap(data, freq, size);
    while (!isSizeOne(minHeap)) {
        left = extractMin(minHeap);
        right = extractMin(minHeap);
        top = newNode('$', left->freq + right->freq);
        top->left = left;
        top->right = right;
        insertMinHeap(minHeap, top);
    }
    return extractMin(minHeap);
}

void printCodes(struct MinHeapNode* root, int arr[], int top) {
    if (root->left) {
        arr[top] = 0;
        printCodes(root->left, arr, top + 1);
    }
    if (root->right) {
        arr[top] = 1;
        printCodes(root->right, arr, top + 1);
    }
    if (isLeaf(root)) {
        printf("%c: ", root->data);
        printArr(arr, top);
    }
}

void HuffmanCodes(char data[], int freq[], int size) {
    struct MinHeapNode* root = buildHuffmanTree(data, freq, size);
    int arr[MAX_TREE_HT], top = 0;
    printCodes(root, arr, top);
}

int main() {
    char arr[] = {'a', 'b', 'c', 'd', 'e', 'f'};
    int freq[] = {5, 9, 12, 13, 16, 45};
    int size = sizeof(arr) / sizeof(arr[0]);
    HuffmanCodes(arr, freq, size);
    return 0;
}

以上代码实现了哈夫曼编码的构建过程，其中 `HuffmanCodes()` 函数用于创建哈夫曼树并输出编码表。 如果您需要对数据进行编码或解码，请参考以下示例代码：

// 哈夫曼编码的结构体定义
struct HuffmanCode {
    char character;
    char code[MAX_TREE_HT];
};

void encode(struct HuffmanCode codes[], char input[], char output[]) {
    int len = strlen(input);
    int i, j, k;
    for (i = 0, k = 0; i < len; i++) {
        for (j = 0; j < MAX_TREE_HT; j++) {
            if (input[i] == codes[j].character) {
                strcpy(output + k, codes[j].code);
                k += strlen(codes[j].code);
                break;
            }
        }
    }
    output[k] = '\0';
}

void decode(struct HuffmanCode codes[], char input[], char output[]) {
    int len = strlen(input);
    int i, j, k;
    for (i = 0, k = 0; i < len; i++) {
        for (j = 0; j < MAX_TREE_HT; j++) {
            if (strncmp(input + i, codes[j].code, strlen(codes[j].code)) == 0) {
                output[k++] = codes[j].character;
                i += strlen(codes[j].code) - 1;
                break;
            }
        }
    }
    output[k] = '\0';
}

使用示例：

char input[] = "abcdef";
char encoded[MAX_TREE_HT * strlen(input)];
char decoded[strlen(input)];

// 构建哈夫曼编码
struct HuffmanCode codes[MAX_TREE_HT];
struct MinHeapNode* root = buildHuffmanTree(arr, freq, size);
int arr[MAX_TREE_HT], top = 0;
printCodes(root, arr, top);
for (int i = 0; i < size; i++) {
    codes[i].character = arr[i];
    strcpy(codes[i].code, "");
    for (int j = 0; j < top; j++) {
        char temp[2];
        sprintf(temp, "%d", arr[j]);
        strcat(codes[i].code, temp);
    }
}

// 进行编码
encode(codes, input, encoded);
printf("Encoded string: %s\n", encoded);

// 进行解码
decode(codes, encoded, decoded);
printf("Decoded string: %s\n", decoded);