首先用python 編寫一個server

import socket  
  
address = ('127.0.0.1', 21567)  
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)  
s.bind(address)  
  
while True:  
    data, addr = s.recvfrom(2048)  
    if not data:  
        print "client has exist"  
        break  
    print "received:", data, "from", addr  
  
s.close()
 

#include<stdio.h>
#include<winsock2.h>
 
#pragma comment(lib,"ws2_32.lib") //Winsock Library
 
#define SERVER "127.0.0.1"  //ip address of udp server
#define BUFLEN 512  //Max length of buffer
#define PORT 21567   //The port on which to listen for incoming data
 
int main(void)
{
    struct sockaddr_in si_other;
    int s, slen=sizeof(si_other);
    char buf[BUFLEN];
    char message[BUFLEN];
    WSADATA wsa;
 
    //Initialise winsock
    printf("\nInitialising Winsock...");
    if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
    {
        printf("Failed. Error Code : %d",WSAGetLastError());
        exit(EXIT_FAILURE);
    }
    printf("Initialised.\n");
     
    //create socket
    if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == SOCKET_ERROR)
    {
        printf("socket() failed with error code : %d" , WSAGetLastError());
        exit(EXIT_FAILURE);
    }
     
    //setup address structure
    memset((char *) &si_other, 0, sizeof(si_other));
    si_other.sin_family = AF_INET;
    si_other.sin_port = htons(PORT);
    si_other.sin_addr.S_un.S_addr = inet_addr(SERVER);
     
    //start communication
    while(1)
    {
        printf("Enter message : ");
        gets(message);
         
        //send the message
        if (sendto(s, message, strlen(message) , 0 , (struct sockaddr *) &si_other, slen) == SOCKET_ERROR)
        {
            printf("sendto() failed with error code : %d" , WSAGetLastError());
            exit(EXIT_FAILURE);
        }
         
        //receive a reply and print it
        //clear the buffer by filling null, it might have previously received data
        memset(buf,'\0', BUFLEN);
        //try to receive some data, this is a blocking call
        if (recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen) == SOCKET_ERROR)
        {
            printf("recvfrom() failed with error code : %d" , WSAGetLastError());
            exit(EXIT_FAILURE);
        }
         
        puts(buf);
    }
 
    closesocket(s);
    WSACleanup();
 
    return 0;
}
 

而後就可以運行了。