UDP通信小程序

udpserver.cpp
#include<Winsock2.h>
#include<stdio.h>
#include<stdlib.h>
#include <WS2tcpip.h>
#pragma comment(lib, "Ws2_32.lib")
using namespace std;
//服务器端口号为5050
#define DEFAULT_PORT  5055
//接收数据缓冲区长度
#define BUFFER_LENGTH  1024
void main()
{
	int iPort = DEFAULT_PORT;
	WSADATA	wsaData;
	SOCKET		sSocket;
	//客户地址长度
	int iLen;
	//发送的数据长度
	int iSend;
	//接收的数据长度
	int iRecv;
	//要发送给客户的信息
	char	send_buf[] = "Hello! I am a server.";
	//接收数据的缓冲区
	char	recv_buf[BUFFER_LENGTH];
	//本地地址和客户地址
	struct sockaddr_in	ser,cli;
	printf("-------------------------------\n");
	printf("Server waiting\n");
	printf("-------------------------------\n");
	if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
	{
		printf("Failed to load Winsock.\n ");
		return;
	}
	//产生服务器端套接口
	sSocket = socket(AF_INET, SOCK_DGRAM, 0);
	if (sSocket == INVALID_SOCKET)
	{
		printf("socket( ) Failed: %d\n", WSAGetLastError());
		return;
	}
	//以下建立服务器端地址
	ser.sin_family = AF_INET;
	//htons( )函数把一个双字节主机字节顺序的数转换为网络字节顺序的数
	//ser.sin_port = htons(iPort);
	ser.sin_port = htons(5055);
	//htonl( )函数把一个主机字节顺序的数转换为网络字节顺序的数
	ser.sin_addr.s_addr = htonl(INADDR_ANY);
	if (bind(sSocket, (LPSOCKADDR)&ser, sizeof(ser)) == SOCKET_ERROR)
	{
		printf("bind( ) Failed: %d\n", WSAGetLastError());
		return;
	}
	iLen = sizeof(cli);
	//初始化接收缓冲区
	memset(recv_buf, 0, sizeof(recv_buf));
	//进入一个无限循环，进行数据接收和发送
	while (1)
	{
		//从客户端接收数据
		iRecv = recvfrom(sSocket, recv_buf, BUFFER_LENGTH, 0,(SOCKADDR*)&cli, &iLen);
		if (iRecv == SOCKET_ERROR)
		{
			printf("recvfrom( ) Failed.:%d\n", WSAGetLastError());
			break;
		}
		else	if (iRecv == 0)
			break;
		else
		{
			char ip[20];
			struct in_addr s;
			s = cli.sin_addr;
			inet_ntop(AF_INET, (void*)&s, ip, 16);
			//输出接收到的数据
			printf("recvfrom( ):%s\n", recv_buf);
			printf("Accepted client IP:[%s],port:[%d]\n", ip, ntohs(cli.sin_port));
			//输出客户IP地址和端口号
			//printf("Accepted client IP:[%s],port:[%d]\n",inet_ntoa(cli.sin_addr),ntohs(cli.sin_port));
		}
		if (strcmp(recv_buf, "bye") == 0)
		{
			closesocket(sSocket);
			break;
		}

		printf("Please input send data:");
		char c = getchar();
		int i = 0;
		while (c != '\n')
		{
			send_buf[i] = c;
			i++;
			c = getchar();
		}
		send_buf[i] = '\0';
		//给客户发送信息
		iSend = sendto(sSocket, send_buf, sizeof(send_buf), 0,(SOCKADDR*)&cli, sizeof(cli));
		if (iSend == SOCKET_ERROR)
		{
			printf("sendto( ) Failed.:%d\n", WSAGetLastError());
			printf("-------------------------------\n");
			break;
		}
		else	if (iSend == 0)
			break;
		else
		{
			printf("sendto( ) succeeded!\n");
			printf("-------------------------------\n");
		}
	}
	printf("通信结束!");
	//closesocket(sSocket);
	WSACleanup();
	system("pause");
}

udpClient.cpp
#include<Winsock2.h>
#include<stdio.h>
#include <WS2tcpip.h>
#pragma comment(lib, "Ws2_32.lib")
#pragma warning(disable:4996)
using namespace std;
//服务器端口号为5050
#define DEFAULT_PORT  5055
//缓冲区长度
#define DATA_BUFFER   1024
void main(int argc, char *argv[])
{
	WSADATA wsaData;
	SOCKET sClient;
	int iPort = 5050;
	//服务器地址长度
	int 		iLen;
	//接收数据的缓冲
	int 		iSend;
	int 		iRecv;
	//要发送给服务器的信息
	char send_buf[] = "Hello! I am a client.";
	//接收数据的缓冲区
	char recv_buf[DATA_BUFFER];
	//服务器端地址
	struct sockaddr_in ser;
	//处理命令行中输入的参数
	/*if (argc < 2)
	{
		//提示在命令行中输入服务器IP地址
		printf("Usage:client [server IP address]\n");
		return;
	}*/
	//接收数据的缓冲区初始化
	memset(recv_buf, 0, sizeof(recv_buf));
	if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
	{
		printf("Failed to load Winsock.\n");
		return;
	}
	//建立服务器端地址
	ser.sin_family = AF_INET;
	//ser.sin_port = htons(iPort);
	ser.sin_port = htons(5055);
	ser.sin_addr.s_addr = inet_addr("127.0.0.1");
	//建立客户端数据报套接口
	sClient = socket(AF_INET, SOCK_DGRAM, 0);
	if (sClient == INVALID_SOCKET)
	{
		printf("socket( )Failed:%d\n", WSAGetLastError());
		return;
	}
	iLen = sizeof(ser);
	while (1)
	{
		//向服务器发送数据
		iSend = sendto(sClient, send_buf, sizeof(send_buf), 0, (struct sockaddr*)&ser, iLen);
		if (iSend == SOCKET_ERROR)
		{
			printf("sendto( )Failed:%d\n", WSAGetLastError());
			return;
		}
		else if (iSend == 0)
			return;
		else
			printf("snedto( ) succeeded.\n");
		//从服务器接收数据
		iRecv = recvfrom(sClient, recv_buf, sizeof(recv_buf), 0, (struct sockaddr*)&ser, &iLen);
		if (iRecv == SOCKET_ERROR)
		{
			printf("recvfrom( )Failed.:%d\n", WSAGetLastError());
			return;
		}
		else	if (iRecv == 0)
			return;
		else
		{
			//显示从服务器收到的信息
			printf("recvfrom( ):%s\n", recv_buf);
			printf("-------------------------------\n");
		}
		if (strcmp(recv_buf, "bye") == 0)
		{
			closesocket(sClient);
			break;
		}
		//给服务器发送数据
		printf("Please input send data:");
		char c = getchar();
		int i = 0;
		while (c != '\n')
		{
			send_buf[i] = c;
			i++;
			c = getchar();
		}
		send_buf[i] = '\0';
		printf("The send data is:%s", send_buf);
	}
	printf("通信结束!");
	//closesocket(sClient);
	WSACleanup();
	system("pause");
}