C语言实现UDP连接的参考代码

C语言实现UDP连接的参考代码，Client连接上Server后将自己所在目录下的"liu"文件中的前三行文字发送到Server端去，然后Server负责接收和显示。

/**************server.c**************/#include<stdio.h>#include<stdlib.h>#include<string.h>#include<sys/socket.h>#include<netinet/in.h>#include<arpa/inet.h>#include<netdb.h>#include<errno.h>#include<sys/types.h>int port=8888;int main(){   int sockfd;   int len;   int z;   char buf[256];   struct sockaddr_in adr_inet;   struct sockaddr_in adr_clnt;   printf("waiting for client...\n");   adr_inet.sin_family=AF_INET;   adr_inet.sin_port=htons(port);   adr_inet.sin_addr.s_addr=htonl(INADDR_ANY);   bzero(&(adr_inet.sin_zero),8);   len=sizeof(adr_clnt);   sockfd=socket(AF_INET,SOCK_DGRAM,0);   if(sockfd==-1){     perror("socket error_1");     exit(1);   }   z=bind(sockfd,(struct sockaddr *)&adr_inet,sizeof(adr_inet));   if(z==-1){     perror("bind error_1");     exit(1);   }   while(1){     z=recvfrom(sockfd,buf,sizeof(buf),0,(struct sockaddr *)&adr_clnt,&len);     if(z<0){       perror("recvfrom error_1");       exit(1);     }     buf[z]=0;     printf("接收：%s",buf);     if(strncmp(buf,"stop",4)==0){       printf("结束....\n");       break;     }   }   close(sockfd);   exit(0);}

/***************client.c***************/#include<stdio.h>#include<stdlib.h>#include<string.h>#include<sys/socket.h>#include<netinet/in.h>#include<arpa/inet.h>#include<netdb.h>#include<errno.h>#include<sys/types.h>int port=8888;int main(int argc,char *argv[]){  int sockfd;  int i=0;  int z;  char buf[80],str1[80];  struct hostent *host;  struct sockaddr_in adr_srvr;  if(argc<2){    fprintf(stderr,"please enter the server's hostname!\n");    exit(1);  }  if((host=gethostbyname(argv[1]))==NULL){    herror("gethostbyname error!");    exit(1);  }  FILE *fp;  printf("open file....\n");  fp=fopen("liu","r");  if(fp==NULL){    perror("failed to open file");    exit(1);  }  printf("connecting server....\n");  adr_srvr.sin_family=AF_INET;  adr_srvr.sin_port=htons(port);  adr_srvr.sin_addr=*((struct in_addr *)host->h_addr);  bzero(&(adr_srvr.sin_zero),8);  sockfd=socket(AF_INET,SOCK_DGRAM,0);  if(sockfd==-1){    perror("socket error!");    exit(1);  }  printf("send file ...\n");  for(i=0;i<3;i++){     fgets(str1,80,fp);     printf("%d:%s",i,str1);     sprintf(buf,"%d:%s",i,str1);     z=sendto(sockfd,buf,sizeof(buf),0,(struct sockaddr *)&adr_srvr,sizeof(adr_srvr));     if(z<0){       perror("recvfrom error");       exit(1);     }  }  printf("send ....\n");  sprintf(buf,"stop\n");  z=sendto(sockfd,buf,sizeof(buf),0,(struct sockaddr *)&adr_srvr,sizeof(adr_srvr));  if(z<0){    perror("sendto error");    exit(1);  }  fclose(fp);  close(sockfd);  exit(0);}

运行截图：

Server端：

Client端：

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