#include <stdio.h>

#include <sys/socket.h>

#include <unistd.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <stdlib.h>

#include <time.h>

#include <string.h>
 

#define SERVER_PORT 20000 // define the defualt connect port id

#define LENGTH_OF_LISTEN_QUEUE 10 //length of listen queue in server

#define BUFFER_SIZE 255

#define WELCOME_MESSAGE "welcome to connect the server. "

 

 

int main(int argc, char **argv)

{
	   char receive[BUFFER_SIZE];
	   char sendata[BUFFER_SIZE];
	   char inputdata;
       int servfd,clifd;
	   int length;


       struct sockaddr_in servaddr,cliaddr;

 

       if ((servfd = socket(AF_INET,SOCK_STREAM,0)) < 0)

       {

              printf("create socket error!\n");

              exit(1);

       }

       bzero(&servaddr,sizeof(servaddr));

       servaddr.sin_family = AF_INET;

       servaddr.sin_port = htons(SERVER_PORT);

       servaddr.sin_addr.s_addr = htons(INADDR_ANY);

 

       if (bind(servfd,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)

       {

              printf("bind to port %d failure!\n",SERVER_PORT);

              exit(1);

       }

 

       if (listen(servfd,LENGTH_OF_LISTEN_QUEUE) < 0)

       {

              printf("call listen failure!\n");

              exit(1);

       }

 

       while (1)

       {//server loop will nerver exit unless any body kill the process

              char buf[BUFFER_SIZE];

              long timestamp;

              socklen_t length = sizeof(cliaddr);

              clifd = accept(servfd,(struct sockaddr*)&cliaddr,&length);

              if (clifd < 0)

              {

                     printf("error comes when call accept!\n");

                     break;

              }

              strcpy(buf,WELCOME_MESSAGE);

              //inet_ntop(INET_ADDRSTRLEN,cliaddr.sin_addr,buf,BUFFER_SIZE);

              

              printf("from client,IP:%s,Port:%d\n",inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));
              timestamp = time(NULL);
              strcat(buf,"timestamp in server:");

              strcat(buf,ctime(&timestamp));
              send(clifd,buf,BUFFER_SIZE,0);
                  /*
		          printf("please input send data:");
	              gets(sendata);
	              int lengthdata;
				  int i =0;
	              lengthdata = strlen(sendata);
	              send(clifd,sendata,lengthdata,0);
				  /*
				  char inputdata;
	              printf("go on please input y,stop client pleaseinput n:");
				  scanf("%c",&inputdata);
				  while(i<3)
				  {
				 
				       if ((inputdata != 'y')& (inputdata != 'n')) 
					   {
					          printf("scanf is wrong !please input again!!\n");
                              scanf("%c",&inputdata);
					          i= i+1;
					   }
				  }
				  if (inputdata =='n'|i>=3) 
				  {       
					  close(clifd);
                      return 0;
				  }
				  if(inputdata == 'y')continue;
				  */
			  while(1)
			  {
				  printf("receive data!\n");
		          length = recv(clifd,receive,BUFFER_SIZE,0);
				  if (length = 0) 
				  {
					  printf("No data!!\n");
				  }
				  else
				  {
					  puts(receive);
					  printf("\n");
				  }
				  printf("write n stop receiving data,other go on!!\n");
					  scanf("%c",&inputdata);
				  if(inputdata == 'n')
				  {				  
					  close(clifd);
                      return 0;
				  }

			  }
     
              

       }//exit

       close(servfd);

       return 0;

}