【socket编程】一个简单的基于UDP的客户/服务端例子(vs2008)

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************************udp_client.cpp************************

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//使用方法举例：udp_client 127.0.0.1 8000
#include <stdio.h>
#include "winsock2.h"
#pragma comment(lib, "ws2_32.lib")//加载依赖库（方法二：项目属性-链接器-输入-附加依赖项：填入ws2_32.lib）

SOCKET udp_socket;
sockaddr_in udpAddr;
const int BufLen=1024;
char SendBuf[BufLen];

int main(int argc,char** argv)
{
 WSADATA wsaData;
 long int Addr;
 int Port;
 if(argc!=3){printf("Usage:%s [<IP> <Port>]\n",argv[0]);return 0;}
 Addr=inet_addr(argv[1]);
 Port=atoi(argv[2]);

 WSAStartup(MAKEWORD(2,2), &wsaData);//根据版本通知操作系统，启用SOCKET的DLL库，必须的
 udp_socket=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);//创建socket
 printf("Running in client mode...\n");

 udpAddr.sin_family=AF_INET;
 udpAddr.sin_port=htons(Port);
 udpAddr.sin_addr.s_addr=Addr;
 while(1)//循环发送
 {
  gets_s(SendBuf,BufLen);
  sendto(udp_socket,SendBuf,BufLen,0,(sockaddr*)&udpAddr,sizeof(udpAddr));//往指定IP的指定端口发送数据
 }
 closesocket(udp_socket);//关闭socket
 return 1;
}

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***********************udp_service.cpp***********************

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#include <stdio.h>
#include "winsock2.h"
#pragma comment(lib, "ws2_32.lib")

SOCKET udpSocket=INVALID_SOCKET;
sockaddr_in udpAddr;
const int BufLen=1024;
char RecvBuf[BufLen];

int main()
{
 WSADATA wsaData;
 int Port=8000;//端口可自己改

 WSAStartup(MAKEWORD(2,2), &wsaData);
 udpSocket=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
 udpAddr.sin_family=AF_INET;
 udpAddr.sin_port=htons(Port);
 printf("Running in service mode...\n");

 bind(udpSocket,(SOCKADDR*)&udpAddr,sizeof(udpAddr));//绑定端口
 int size=sizeof(udpAddr);
 while(1)//循环接收
 {
  if(udpSocket==INVALID_SOCKET){
   Sleep(1000);//等待，处理端口信息留出时间
   continue;//跳到下一次while，而不是下一行语句
  }
  recvfrom(udpSocket,RecvBuf,BufLen,0,(SOCKADDR*)&udpAddr,&size);//接收信息
  printf("Received:%s\n",RecvBuf);
 }
 closesocket(udpSocket);
 return 1;
}