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C++网络通信：TCP数据包的发送与接收编程

ops 2025/6/28 11:15:40

在C++中实现TCP网络通信涉及创建客户端和服务端程序，以实现数据的发送和接收。下面是一个简单的示例，展示如何使用C++进行TCP通信。这个示例包括一个简单的TCP客户端和TCP服务端。

TCP服务端

【cpp】
#include <iostream>
#include <string>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <cstring>

int main() {
int server_fd, new_socket;
struct sockaddr_in address;
int opt = 1;
int addrlen = sizeof(address);
char buffer[1024] = {0};

// 创建socket文件描述符
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
perror("socket failed");
exit(EXIT_FAILURE);
}

// 设置socket选项
if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
perror("setsockopt");
exit(EXIT_FAILURE);
}

address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8080);

// 绑定socket到端口
if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}

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

std::cout << "Server is listening on port 8080..." << std::endl;

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

while (true) {
// 读取客户端发送的数据
int valread = read(new_socket, buffer, sizeof(buffer));
if (valread <= 0) {
break; // 连接关闭或出错
}

std::cout << "Received from client: " << buffer << std::endl;

// 发送响应
const char *response = "Hello from server";
send(new_socket, response, strlen(response), 0);
std::cout << "Response sent to client" << std::endl;

// 清空缓冲区
memset(buffer, 0, sizeof(buffer));
}

close(new_socket);
close(server_fd);
return 0;
}

TCP客户端

【cpp】
#include <iostream>
#include <string>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <cstring>

int main() {
int sock = 0;
struct sockaddr_in serv_addr;
char buffer[1024] = {0};

// 创建socket
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
std::cout << "Socket creation error" << std::endl;
return -1;
}

serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(8080);

// 将IPv4地址从文本转换为二进制形式
if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
std::cout << "Invalid address/ Address not supported" << std::endl;
return -1;
}

// 连接到服务器
if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
std::cout << "Connection Failed" << std::endl;
return -1;
}

// 发送数据
const char *message = "Hello from client";
send(sock, message, strlen(message), 0);
std::cout << "Message sent to server" << std::endl;

// 读取响应
int valread = read(sock, buffer, sizeof(buffer));
std::cout << "Received from server: " << buffer << std::endl;

close(sock);
return 0;
}

代码说明

1. 服务端：

• 创建一个socket并绑定到指定的端口（这里是8080）。

• 监听连接请求，并接受客户端的连接。

• 循环读取客户端发送的数据，并发送响应。

2. 客户端：

• 创建一个socket并连接到服务端（假设服务端运行在本地主机上）。

• 发送数据到服务端，并读取服务端的响应。