C++ 网络编程入门（笔记）

贡献者： addis

　　 参考这篇文章。

// Server side C/C++ program to demonstrate Socket
// programming
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080
int main(int argc, char const* argv[])
{
	int server_fd, new_socket, valread;
	struct sockaddr_in address;
	int opt = 1;
	int addrlen = sizeof(address);
	char buffer[1024] = { 0 };
	char* hello = "Hello from server";

	// Creating socket file descriptor
	if ((server_fd = socket(AF_INET, SOCK_STREAM, 0))
		== 0) {
		perror("socket failed");
		exit(EXIT_FAILURE);
	}

	// Forcefully attaching socket to the port 8080
	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(PORT);

	// Forcefully attaching socket to the port 8080
	if (bind(server_fd, (struct sockaddr*)&address,
			sizeof(address))
		< 0) {
		perror("bind failed");
		exit(EXIT_FAILURE);
	}
	if (listen(server_fd, 3) < 0) {
		perror("listen");
		exit(EXIT_FAILURE);
	}
	if ((new_socket
		= accept(server_fd, (struct sockaddr*)&address,
				(socklen_t*)&addrlen))
		< 0) {
		perror("accept");
		exit(EXIT_FAILURE);
	}
	valread = read(new_socket, buffer, 1024);
	printf("%s\n", buffer);
	send(new_socket, hello, strlen(hello), 0);
	printf("Hello message sent\n");
	
// closing the connected socket
	close(new_socket);
// closing the listening socket
	shutdown(server_fd, SHUT_RDWR);
	return 0;
}

// Client side C/C++ program to demonstrate Socket
// programming
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main(int argc, char const* argv[])
{
	int sock = 0, valread, client_fd;
	struct sockaddr_in serv_addr;
	char* hello = "Hello from client";
	char buffer[1024] = { 0 };
	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
		printf("\n Socket creation error \n");
		return -1;
	}

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

	// Convert IPv4 and IPv6 addresses from text to binary
	// form
	if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr)
		<= 0) {
		printf(
			"\nInvalid address/ Address not supported \n");
		return -1;
	}

	if ((client_fd
		= connect(sock, (struct sockaddr*)&serv_addr,
				sizeof(serv_addr)))
		< 0) {
		printf("\nConnection Failed \n");
		return -1;
	}
	send(sock, hello, strlen(hello), 0);
	printf("Hello message sent\n");
	valread = read(sock, buffer, 1024);
	printf("%s\n", buffer);

	// closing the connected socket
	close(client_fd);
	return 0;
}

g++ server.cpp -o server
g++ client.cpp -o client