Linux-网络编程-UDP网络编程（day13续2）

服务器代码　
 1 #include<stdio.h>
  2 #include<sys/socket.h>
  3 #include<syspes.h>
  4 #include<netinet/in.h>
  5 #include<unistd.h>
  6 #include<arpa/inet.h>
  7 #include<ctype.h>
  8 
  9 typedef struct sockaddr_in SA4;
 10 typedef struct sockaddr SA;
 11 int main(void){
 12     int s_fd;
 13     //创建通讯描述符
 14     SA4 server,client;
 15     char buf[128];
 16     s_fd=socket(AF_INET,0);
 17     if(s_fd==-1){
 18         perror("socket");
 19         return 1;
 20     }   
 21     //初始化server的地址空间
 22    server.sin_family=AF_INET;
 23     server.sin_port=htons(7776);
 24     server.sin_addr.s_addr=htonl(INADDR_ANY);
 25     //绑定
 26     int b=bind(s_fd,(SA *)&server,sizeof(server));
 27     if(b==-1){
 28         perror("bind");
 29         return 2;
 30     }
 31     int clilen=sizeof(client);//值结果参数没有必要>    赋值吧
 32     //等待客户端的请求到来
 33     int r;
 34     while((r=recvfrom(s_fd,buf,128,0,(SA *)&client,&clilen))>0){
 35         for(int i=0;i<r;i++){
 36             buf[i]=toupper(buf[i]);
 37 
 38         }
 39         sendto(s_fd,r,sizeof(cl    ient));
 40     }
 41 
 42     close(s_fd);
 43     return 0;
 44  }



客户端代码

　1　#include<stdio.h>
  2 #include<unistd.h>
  3 #include<syspes.h>
  4 #include<sys/socket.h>
  5 #include<string.h>
  6 #include<netinet/in.h>
  7 #include<arpa/inet.h>
  8 
  9 typedef struct sockaddr SA;
 10 typedef struct sockaddr_in SA4;
 11 int main(int argc,char *argv[]){
 12     char buf[]="this is a test!n";
 13     char rbuf[128];
 14     //创建通讯描述符
 15     int s_fd;
 16     SA4 server;
 17     server.sin_family=AF_INET;
 18     server.sin_port=htons(7776);
 19     inet_pton(AF_INET,argv[1],&server.sin_addr);
 20     s_fd=socket(AF_INET,0);
 21     if(s_fd==-1){
22         perror("socket");
 23         return 1;
 24     }
 25     //向服务器发送消息
 26     sendto(s_fd,strlen(buf+1),(SA *)&server,s    izeof(server));
 27     //从服务器获取相应消息
 28     int r;
 29     r=recvfrom(s_fd,rbuf,0,NULL,NULL);
 30     write(1,r);
 31     printf("n");
 32     close(s_fd);
 33 
 34     return 0;
 35 }