Socket之UDP通信例子

UDP通信方式：

1，客户端不需要进行连接，而是直接访问服务器通过sendto来发送数据，recvfrom接受数据

2，服务端，不需要监听、接受等待客户端请求，当收到客户端socket通过sendto来回应客户端请求。

Client端：

#include 
#include 

#pragma comment(lib, "WS2_32.lib")
const unsigned int PORT = 11024;
const int kBufferSize	= 1024;

int main() {

	WSADATA wsData;
	if(WSAStartup(MAKEWORD(2, 2), &wsData) != 0) {
		std::cout << "start up failed\n" << std::endl;
		return 0;
	}
	// connect the socket;

	SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	SOCKADDR_IN addIn;
	addIn.sin_family = AF_INET;
	addIn.sin_port = htons(PORT);
	addIn.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	
	char cSendBuffer[kBufferSize] = "Client sends a Message to the Server, please confirm?";
	int bRecvLen = sizeof(addIn);
	int bSendRet = sendto(s, cSendBuffer, kBufferSize, 0, (LPSOCKADDR)&addIn, sizeof(addIn));
	while(bSendRet != SOCKET_ERROR) {
		char cRecvBuffer[kBufferSize] = "#";
		int bRecv = recvfrom(s, cRecvBuffer, kBufferSize, 0, (LPSOCKADDR)&addIn, &bRecvLen);
		if(bRecv != SOCKET_ERROR) {
			std::cout << "Client recvie the infromation from the server is: " << cRecvBuffer << std::endl;
			ZeroMemory(cSendBuffer, kBufferSize);
			std::cout << "please input the information the sends to the server: ";
			std::cin >> cSendBuffer;
			bSendRet = sendto(s, cSendBuffer, kBufferSize, 0, (LPSOCKADDR)&addIn, sizeof(addIn));
		} else{
			break;
		}
	}

	if(WSACleanup() != 0) {
		std::cout << "clean up failed\n";
		return -1;
	}
	closesocket(s);
	return 0;
}

Server端：

#include 
#include 

#pragma comment(lib, "WS2_32.lib")

const unsigned int PORT = 11024;
const int kBufferSize	= 1024;

int main() {
	WSADATA wsData;
	if(WSAStartup(MAKEWORD(2, 2), &wsData) != 0) {
		std::cout << "start failed" << std::endl;
		return -1;
	}
	//
	SOCKET s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	SOCKADDR_IN addIn;
	
	addIn.sin_family = AF_INET;
	addIn.sin_port = htons(PORT);
	addIn.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	int bBindRet = bind(s, (LPSOCKADDR) &addIn, sizeof(addIn));
	if(bBindRet != 0) {
		std::cout << "bind failed" << std::endl;
		return -1;
	}

	char cRecvBuffer[kBufferSize];
	int ilen = sizeof(addIn);				
	int iRecv = recvfrom(s, cRecvBuffer, kBufferSize, 0, (LPSOCKADDR)&addIn, &ilen);
	while(iRecv != SOCKET_ERROR) {
		std::cout << "recvie information: " << std::endl;
		char cSendBuffer[kBufferSize];
		std::cout << "Input the information that the client sends; " << std::endl;
		std::cin >> cSendBuffer;
		sendto(s, cSendBuffer, kBufferSize, 0, (LPSOCKADDR)&addIn, sizeof(addIn));
	}

	if(WSACleanup() != 0) {
		std::cout << "Clean up failed" << std::endl;
		return -1;
	}

	return 0;
}