Linux Socket编程简单实例

 

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<netdb.h>


char *host_name="127.0.0.1";
int port=7778;

struct student
{
 char name[20];
 char num[20];
 float score;
}t={"xiejian","200701415",89.9};

int main ( )
{
 char buf[502];
 int socket_descriptor;
 struct sockaddr_in pin;
 bzero(&pin,sizeof(pin));
 pin.sin_family=AF_INET;
 inet_pton(AF_INET,host_name,&pin.sin_addr);
 pin.sin_port=htons(port);
 if((socket_descriptor=socket(AF_INET,SOCK_STREAM,0))==-1)
 {
  perror("Error openung socket!/n");
  exit(1);
 }
 if(connect(socket_descriptor,(void *)&pin,sizeof (pin))==-1)
 {
  perror("can not connecting to server!/n");
  exit (1);
 }
 printf("Send message  to server .../n");
 //memset(buf,0,502);
 //memcpy(buf,(void *)&t,sizeof(t));
 //sprintf(buf,"%s %d",t.name,t.num);
 //printf("the first string : %s/n",buf);
 if(send(socket_descriptor,(void *) &t,sizeof(t),0)==-1)
 {
  perror("can not send message!/n");
  exit (1);
 }
 printf("waiting for response from server!/n");
 memset(buf,0,502);
 if(recv(socket_descriptor,buf,sizeof(buf),0)==-1)
 {
  perror("can not receive response !/n");
  exit (1);
 }
 printf("/n Response from server : /n");
 memcpy((struct student *)&t,buf,sizeof(buf));
 //printf("the string : %s /n",rebuf);
 printf("--%s--%s--%5.1f--/n",t.name,t.num,t.score);
 close (socket_descriptor);
} 

/*  注意在send 结构体时应该把结构体强制类型转换为void * 型 
**  接受之后又要强制转换回结构体型！否则则穿过来的是结构体的
**  一部分！
*/


下面是服务端
#include<stdio.h>
#include<stdlib.h>
#include<netinet/in.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netdb.h>


int port=7778;
struct student
{
 char name[20];
 char num[20];
 float score;
}t;

main()
{
 struct sockaddr_in sin;
 struct sockaddr_in pin;
 int sock_descriptor;
 int temp_sock_descriptor;
 int size_of_addr;
 //struct cfg a;
 char buf[502];
 int i,lenth;
 sock_descriptor=socket(AF_INET,SOCK_STREAM,0);
 if(sock_descriptor==-1)
 { 
  perror("socket!/n");
  exit(1);
 }
 bzero(&sin,sizeof(sin));
 sin.sin_addr.s_addr=INADDR_ANY;
 sin.sin_port=htons(port);
 if(bind(sock_descriptor,(struct sockaddr *)&sin,sizeof (sin))==-1)
 {
  perror("bind!/n");
  exit(1);
 }
 if(listen (sock_descriptor,20)==-1)
 {
  perror("listen!/n");
  exit(1);
 }
 printf("Waiting for accepting connection from client!/n");
 while(1)
 {
  printf("the process is waiting here!/n");
  temp_sock_descriptor=accept(sock_descriptor, (struct sockaddr *)&pin,&size_of_addr);
  if(temp_sock_descriptor==-1)
  {
   perror("call to accept!/n");
   exit (1);
  }
  memset(buf,0,502);
  if(recv(temp_sock_descriptor,buf,sizeof(buf),0)==-1)
  {
   perror("recv!/n");
   exit (1);
  }
  
  printf("received : /n");
  //printf("the recv buf is :%s/n",buf);
  memcpy((struct student *) &t,buf,sizeof(buf));
  printf("--%s--%s--%5.1f--/n",t.name,t.num,t.score);
  if(send (temp_sock_descriptor,(void *) &t,sizeof(t),0)==-1)
  {
   perror("send!/n");
   exit(1);
  }
  close (temp_sock_descriptor);
 }
}