windows下的udp通讯简单示例

很久没有手写udp通讯了，而且以前也没有在windows下写过，今天写一下，熟悉一下

• 发送端代码：

#include 
#include 
#include 
#pragma comment(lib, "ws2_32.lib")

using namespace std;


int main()
{

	WSADATA WSAdata;
	if (!WSAStartup(MAKEWORD(2, 2), &WSAdata))
	{
		cout << "初始化成功" << endl;
	}
	else
	{
		cout << "初始化失败！" << endl;
		exit(1);
	}
	SOCKET send_sock = -1;
	send_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (send_sock == INVALID_SOCKET)
	{
		cout << "socket fail" << endl;
		exit(1);
	}
	cout << "sock: " << send_sock << endl;

	//要发送到的地址信息
	SOCKADDR_IN to;
	to.sin_family = AF_INET;
	to.sin_port = htons(8888);
	to.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    
    //可选项，udp建立连接后，理论上效率会更高
    //connect(send_sock, (sockaddr *)&to, sizeof to);

	while (1)
	{
		//发送数据
		char buf[1024] = "";
		cout << "请输入：";
		cin >> buf;
		int num = sendto(send_sock, buf, strlen(buf), 0, (sockaddr *)&to, sizeof to);
		cout << "发送的字节数： " << num << endl;
	}

	closesocket(send_sock);
	WSACleanup();
	system("pause");
	return 0;
}

• 接收端代码：

#include 
#include 
#include 
#pragma comment(lib, "ws2_32.lib")

using namespace std;

int main()
{
	WSADATA WSAdata;
	if (!WSAStartup(MAKEWORD(2, 2), &WSAdata))
	{
		cout << "初始化成功" << endl;
	}
	else
	{
		cout << "初始化失败" << endl;
		exit(1);
	}

	SOCKET server_sock = -1;
	server_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (server_sock == INVALID_SOCKET) //这个值是-1
	{
		cout << "socket fail" << endl;
		exit(1);
	}
	cout << "server socket: " << endl;

	//绑定的地址
	SOCKADDR_IN server_addr;
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(8888);
	server_addr.sin_addr.S_un.S_addr = INADDR_ANY;
	bind(server_sock, (sockaddr *)&server_addr, sizeof server_addr);

	char buf[1024] = "";
	while (1)
	{
		int num = -1;
		memset(buf, 0, sizeof buf);
		num = recv(server_sock, buf, sizeof buf, 0);
		cout << "接收到的字节数： " << num << "字节" << endl;
		cout << "接收到的数据： " << buf << endl;
	}

	closesocket(server_sock);
	WSACleanup();
	system("pause");
	return 0;
}

• 运行结果

• 添加一个发送文件的代码：

#define _CRT_SECURE_NO_WARNINGS
#include 
#include 
#include 
#pragma comment(lib, "ws2_32.lib")

using namespace std;


int main()
{

	WSADATA WSAdata;
	if (!WSAStartup(MAKEWORD(2, 2), &WSAdata))
	{
		cout << "初始化成功" << endl;
	}
	else
	{
		cout << "初始化失败！" << endl;
		exit(1);
	}
	SOCKET send_sock = -1;
	send_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (send_sock == INVALID_SOCKET)
	{
		cout << "socket fail" << endl;
		exit(1);
	}
	cout << "sock: " << send_sock << endl;

	//要发送到的地址信息
	SOCKADDR_IN to;
	to.sin_family = AF_INET;
	to.sin_port = htons(8888);
	to.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");

	//打开文件
	FILE *fd = fopen("UDPTrans.cpp", "rb");
	if (fd == NULL)
	{
		perror("fopen");
		exit(1);
	}
	int num = -1;
	getchar();
	while (!feof(fd))
	{
		//发送数据
		char buf[1024] = "";
		num = fread(buf, sizeof buf - 1, 1, fd);
		cout << buf << endl;

		num = sendto(send_sock, buf, strlen(buf), 0, (sockaddr *)&to, sizeof to);
		cout << buf << endl;
	}

	closesocket(send_sock);
	WSACleanup();
	system("pause");
	return 0;
}