服务器

socket(AF_INET,SOCK_DGRAM,0);if(oldfd

-1;}//绑定struct

*)server,sizeof(server))-1){perror(bind);return

-1;}struct

0;while(1){recvfrom(oldfd,buff,sizeof(buff),0,(struct

sockaddr

*)client,client_len);printf(%s:%d信息%s\n,inet_ntoa(client.sin_addr),ntohs(client.sin_port),buff);if(connect(oldfd,(struct

sockaddr

*)client,sizeof(client))-1){perror(connect);return

-1;}while(1){int

recvfrom(oldfd,buff,sizeof(buff),0,NULL,NULL);printf(%s\n,buff);strcat(buff,周日还要上课吴);sendto(oldfd,buff,sizeof(buff),0,NULL,0);bzero(buff,sizeof(buff));if(res

0){printf(退出客户端\n);break;}}}return

}客户端

socket(AF_INET,SOCK_DGRAM,0);if(oldfd-1){perror(socket);return

-1;}//2、收发消息struct

inet_addr(IP)};if(connect(oldfd,(struct

sockaddr

*)server,sizeof(server))-1){perror(connect);return

-1;}

buff[1024];while(1){fgets(buff,sizeof(buff),stdin);buff[strlen(buff)-1]

\0;sendto(oldfd,buff,sizeof(buff),0,(struct

sockaddr

*)server,sizeof(server));bzero(buff,sizeof(buff));recvfrom(oldfd,buff,sizeof(buff),0,NULL,NULL);printf(接收服务器信息%s\n,buff);}return

}笔记整理

3、收发消息由于不知道对方是谁对方也不知道您是谁所以在发送时附带自己的信息接收时接收对方信息。

UDP相关API

socket(AF_INET,SOCK_DGRAM,0);if(oldfd-1){perror(socket);return

-1;}//2、绑定struct

inet_addr(IP)};if(bind(oldfd,(struct

sockaddr

*)server,sizeof(server))-1){perror(bind);return

-1;}//收发消息struct

buff[1024];while(1){//接收客户端消息时会将客户端信息写入clientrecvfrom(oldfd,buff,sizeof(buff),0,(struct

sockaddr

*)client,client_len);printf(收到%s%d的消息%s\n,inet_ntoa(client.sin_addr),ntohs(client.sin_port),buff);strcat(buff,元旦不放假难受);sendto(oldfd,buff,sizeof(buff),0,(struct

sockaddr

*)client,sizeof(client));//收到谁的信息就发给谁}return

4、UDP客户端

socket(AF_INET,SOCK_DGRAM,0);if(oldfd-1){perror(socket);return

-1;}//2、收发消息struct

buff[1024];while(1){fgets(buff,sizeof(buff),stdin);buff[strlen(buff)-1]

\0;sendto(oldfd,buff,sizeof(buff),0,(struct

sockaddr

*)server,sizeof(server));bzero(buff,sizeof(buff));recvfrom(oldfd,buff,sizeof(buff),0,NULL,NULL);printf(接收服务器信息%s\n,buff);}return

思维导图