用Deepseek实现：用C语言写出TCP和UDP的发送接收代码

以下是使用 C 语言编写的 TCP 和 UDP 的发送和接收示例代码。这些代码基于 Linux 系统的 Socket API。

1. TCP 发送和接收
   TCP 服务器（接收端）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int server_fd, new_socket;
    struct sockaddr_in address;
    int addrlen = sizeof(address);
    char buffer[BUFFER_SIZE] = {0};
    char *response = "Message received";

    // 创建 TCP socket
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("Socket failed");
        exit(EXIT_FAILURE);
    }

    // 绑定 IP 和端口
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
        perror("Bind failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }

    // 监听连接
    if (listen(server_fd, 3) < 0) {
        perror("Listen failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }

    printf("Waiting for a connection...\n");

    // 接受连接
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
        perror("Accept failed");
        close(server_fd);
        exit(EXIT_FAILURE);
    }

    // 接收数据
    int valread = read(new_socket, buffer, BUFFER_SIZE);
    printf("Received: %s\n", buffer);

    // 发送响应
    send(new_socket, response, strlen(response), 0);
    printf("Response sent\n");

    // 关闭 socket
    close(new_socket);
    close(server_fd);
    return 0;
}

TCP 客户端（发送端）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int sock = 0;
    struct sockaddr_in serv_addr;
    char *message = "Hello from client";
    char buffer[BUFFER_SIZE] = {0};

    // 创建 TCP socket
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);
    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
        perror("Invalid address/ Address not supported");
        close(sock);
        exit(EXIT_FAILURE);
    }

    // 连接到服务器
    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        perror("Connection failed");
        close(sock);
        exit(EXIT_FAILURE);
    }

    // 发送数据
    send(sock, message, strlen(message), 0);
    printf("Message sent\n");

    // 接收响应
    int valread = read(sock, buffer, BUFFER_SIZE);
    printf("Server response: %s\n", buffer);

    // 关闭 socket
    close(sock);
    return 0;
}

2. UDP 发送和接收
   UDP 服务器（接收端）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in servaddr, cliaddr;
    char buffer[BUFFER_SIZE];
    socklen_t len = sizeof(cliaddr);

    // 创建 UDP socket
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    // 绑定 IP 和端口
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);
    if (bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
        perror("Bind failed");
        close(sockfd);
        exit(EXIT_FAILURE);
    }

    printf("Waiting for data...\n");

    // 接收数据
    int n = recvfrom(sockfd, buffer, BUFFER_SIZE, 0, (struct sockaddr *)&cliaddr, &len);
    buffer[n] = '\0';
    printf("Received: %s\n", buffer);

    // 发送响应
    const char *response = "Message received";
    sendto(sockfd, response, strlen(response), 0, (struct sockaddr *)&cliaddr, len);
    printf("Response sent\n");

    // 关闭 socket
    close(sockfd);
    return 0;
}

UDP 客户端（发送端）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define PORT 8080
#define BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in servaddr;
    char *message = "Hello from client";
    char buffer[BUFFER_SIZE];

    // 创建 UDP socket
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(PORT);
    if (inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr) <= 0) {
        perror("Invalid address/ Address not supported");
        close(sockfd);
        exit(EXIT_FAILURE);
    }

    // 发送数据
    sendto(sockfd, message, strlen(message), 0, (struct sockaddr *)&servaddr, sizeof(servaddr));
    printf("Message sent\n");

    // 接收响应
    socklen_t len = sizeof(servaddr);
    int n = recvfrom(sockfd, buffer, BUFFER_SIZE, 0, (struct sockaddr *)&servaddr, &len);
    buffer[n] = '\0';
    printf("Server response: %s\n", buffer);

    // 关闭 socket
    close(sockfd);
    return 0;
}

3. 运行说明
   编译代码：

gcc tcp_server.c -o tcp_server
gcc tcp_client.c -o tcp_client
gcc udp_server.c -o udp_server
gcc udp_client.c -o udp_client

运行服务器和客户端：

对于 TCP：

./tcp_server
./tcp_client

对于 UDP：

./udp_server
./udp_client

4. 注意事项
   确保端口号未被占用。

如果运行在本地，IP 地址为 127.0.0.1。

需要 root 权限才能绑定低于 1024 的端口号。