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
#include
#include
#include
#include
#include
#include
#include
#include
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
#include
#include
#include
#include
#include
#include
#include
#include
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：
(————完————)
