C语言编程实现 输入：长度为4的任意二进制序列。 输出：输入数据经Hamming(7，4）编码器编码之后，通过二元对称信道模拟器（错误概率为0.1）传输后，再经过Hamming(7，4）译码器译码输出得到信宿端的长度为4的二进制序列。

以下是C语言实现代码：

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

#define N 7    //编码器编码后的长度
#define K 4    //编码器编码前的长度
#define P 0.1  //错误概率

//生成随机01序列
void generate_random_sequence(int seq[], int len) {
    srand((unsigned int) time(NULL));
    for (int i = 0; i < len; i++) {
        seq[i] = rand() % 2;
    }
}

//计算校验位
int calculate_parity_bit(int seq[], int len, int start) {
    int sum = 0;
    for (int i = start; i < len; i += start * 2) {
        for (int j = 0; j < start; j++) {
            if (seq[i + j] == 1) {
                sum++;
            }
        }
    }
    return sum % 2;
}

//Hamming编码器
void hamming_encoder(int input[], int output[]) {
    for (int i = 0; i < K; i++) {
        output[i + 3] = input[i];
    }
    output[0] = calculate_parity_bit(output, N, 1);
    output[1] = calculate_parity_bit(output, N, 2);
    output[3] = calculate_parity_bit(output, N, 4);
    output[7] = calculate_parity_bit(output, N, 8);
}

//二元对称信道模拟器
void binary_symmetric_channel(int input[], int output[], int len, float error_prob) {
    srand((unsigned int) time(NULL));
    for (int i = 0; i < len; i++) {
        if ((float) rand() / RAND_MAX < error_prob) {  //以一定概率翻转每一位
            output[i] = (input[i] + 1) % 2;
        } else {
            output[i] = input[i];
        }
    }
}

//计算Hamming距离
int calculate_hamming_distance(int seq1[], int seq2[], int len) {
    int count = 0;
    for (int i = 0; i < len; i++) {
        if (seq1[i] != seq2[i]) {
            count++;
        }
    }
    return count;
}

//查找错误位置
int find_error_position(int syndrome[]) {
    if (syndrome[0] == 0 && syndrome[1] == 0 && syndrome[2] == 0) {
        return 0;
    }
    if (syndrome[0] == 0 && syndrome[1] == 0 && syndrome[2] == 1) {
        return 4;
    }
    if (syndrome[0] == 0 && syndrome[1] == 1 && syndrome[2] == 0) {
        return 2;
    }
    if (syndrome[0] == 0 && syndrome[1] == 1 && syndrome[2] == 1) {
        return 6;
    }
    if (syndrome[0] == 1 && syndrome[1] == 0 && syndrome[2] == 0) {
        return 1;
    }
    if (syndrome[0] == 1 && syndrome[1] == 0 && syndrome[2] == 1) {
        return 5;
    }
    if (syndrome[0] == 1 && syndrome[1] == 1 && syndrome[2] == 0) {
        return 3;
    }
    if (syndrome[0] == 1 && syndrome[1] == 1 && syndrome[2] == 1) {
        return 7;
    }
    return -1;
}

//Hamming译码器
void hamming_decoder(int input[], int output[]) {
    int syndrome[3] = {0};  //计算校验位
    syndrome[0] = (input[0] + input[2] + input[4] + input[6]) % 2;
    syndrome[1] = (input[1] + input[2] + input[5] + input[6]) % 2;
    syndrome[2] = (input[3] + input[4] + input[5] + input[6]) % 2;
    int error_position = find_error_position(syndrome);  //查找错误位置
    if (error_position == -1) {  //没有出错
        for (int i = 0; i < K; i++) {
            output[i] = input[i + 3];
        }
    } else {  //出错
        input[error_position + 3] = (input[error_position + 3] + 1) % 2;  //纠正错误
        for (int i = 0; i < K; i++) {
            output[i] = input[i + 3];
        }
    }
}

int main() {
    int input[K] = {0};  //输入数据
    int encoded[N] = {0};  //编码后的数据
    int received[N] = {0};  //接收到的数据
    int decoded[K] = {0};  //译码后的数据

    printf("请输入长度为4的任意二进制序列：");
    for (int i = 0; i < K; i++) {
        scanf("%d", &input[i]);
    }

    hamming_encoder(input, encoded);  //编码
    printf("编码后的数据：");
    for (int i = 0; i < N; i++) {
        printf("%d", encoded[i]);
    }
    printf("\n");

    binary_symmetric_channel(encoded, received, N, P);  //模拟信道传输
    printf("接收到的数据：");
    for (int i = 0; i < N; i++) {
        printf("%d", received[i]);
    }
    printf("\n");

    hamming_decoder(received, decoded);  //译码
    printf("译码后的数据：");
    for (int i = 0; i < K; i++) {
        printf("%d", decoded[i]);
    }
    printf("\n");

    int dist = calculate_hamming_distance(encoded, received, N);  //计算汉明距离
    printf("编码前后的汉明距离：%d\n", dist);

    return 0;
}

运行程序后，输入长度为4的任意二进制序列，程序将自动进行Hamming编码器编码、二元对称信道模拟器传输、Hamming译码器译码，并输出编码前后的汉明距离以及译码后的数据。