UDP服务器端和客户端

//客户端

#include <iostream>
#include <stdio.h>
#include <windows.h>
#include <string.h>

using namespace std;

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

class CInitSock
{
public:
 CInitSock(int version01 = 2, int versiont02 = 2)
 {
  WORD sockVersion = MAKEWORD(2, 2);
  WSADATA wsaData = {0}; 

  if (WSAStartup(sockVersion, &wsaData) != 0)
  {
   cout << "initlization failed!" << endl;

   exit(0);
  }
  
 }

 ~CInitSock()
 {
  WSACleanup();
 }
};

CInitSock mysock;

int const MAX_SIZE = 1024;

int main()
{
 char buffer[MAX_SIZE] = "/0";
 sockaddr_in addr = {0};
 int nLen  = sizeof(sockaddr_in);
 SOCKET s;

 addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
 addr.sin_family = AF_INET;
 addr.sin_port  = htons(4567);
 s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

 while (true)
 {
  cout << "Please input send data: " << endl;
  cin >> buffer;

  if ((strcmp(buffer, "quit") == 0) || (strcmp(buffer, "exit")) == 0)
  {
   cout << "process exit...." << endl;

   break;
  }

  sendto(s, buffer, strlen(buffer), 0, (sockaddr*)&addr, sizeof(addr));
 }
} 

//服务器端：

#include <iostream>
#include <stdio.h>
#include <windows.h>

using namespace std;

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

class CInitSock
{
public:
 CInitSock(int version01 = 2, int versiont02 = 2)
 {
  WORD sockVersion = MAKEWORD(2, 2);
  WSADATA wsaData = {0}; 

  if (WSAStartup(sockVersion, &wsaData) != 0)
  {
   cout << "initlization failed!" << endl;

   exit(0);
  }
  
 }

 ~CInitSock()
 {
  WSACleanup();
 }
};

CInitSock mysock;

int main()
{
 SOCKET  s = 0;
 sockaddr_in sin = {0}; 

 sin.sin_family = AF_INET;
 sin.sin_port = htons(4567);
 sin.sin_addr.S_un.S_addr = INADDR_ANY;

 s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

 if (bind(s, (LPSOCKADDR)&sin, sizeof(sin)) == SOCKET_ERROR)
 {
  cout << "bind failed!" << endl;

  return 0;
 }

 char  buffer[1024] = "/0";
 sockaddr_in addr  = {0};
 int  nLen  = 0;

 nLen = sizeof(sockaddr_in);

 cout << "------- now service start -------------" << endl;

 while (true)
 {
  int nRecv = 0;

  cout << "wait to receive data............" << endl;

  nRecv = recvfrom(s, buffer, 1024, 0, (sockaddr*)&addr, &nLen);

  if (nRecv > 0)
  {
   buffer[nRecv] = '/0';

   cout << "receve buffer: " << buffer << endl;
  }
 }

 closesocket(s);

}