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  /*
	File Name: server.c
  ,*/
  #include<stdio.h>
  #include<stdlib.h>
  #include<string.h>
  #include<errno.h>
  #include<sys/types.h>
  #include<sys/socket.h>
  #include<netinet/in.h>
  #include<unistd.h>

  #define DEFAULT_PORT 8000
  #define MAXLINE 4096

  int main(int argc, char** argv) {
	  int    socket_fd, connect_fd;
	  struct sockaddr_in     servaddr;
	  char    buff[4096];
	  int     n;
	  //初始化Socket
	  if( (socket_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ) {
		  printf("create socket error: %s(errno: %d)\n",strerror(errno),errno);
		  exit(0);
	  }
	  //初始化
	  memset(&servaddr, 0, sizeof(servaddr));
	  servaddr.sin_family = AF_INET;
	  servaddr.sin_addr.s_addr = htonl(INADDR_ANY);//IP地址设置成INADDR_ANY,让系统自动获取本机的IP地址。
	  servaddr.sin_port = htons(DEFAULT_PORT);//设置的端口为DEFAULT_PORT

	  //将本地地址绑定到所创建的套接字上
	  if( bind(socket_fd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1) {
		  printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);
		  exit(0);
	  }
	  //开始监听是否有客户端连接
	  if( listen(socket_fd, 10) == -1) {
		  printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);
		  exit(0);
	  }
	  printf("======waiting for client's request======\n");
	  while(1) {
		  //阻塞直到有客户端连接，不然多浪费CPU资源。
		  if( (connect_fd = accept(socket_fd, (struct sockaddr*)NULL, NULL)) == -1) {
			  printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
			  continue;
		  }
		  //接受客户端传过来的数据
		  n = recv(connect_fd, buff, MAXLINE, 0);
		  //向客户端发送回应数据
		  if(!fork()) { //子进程
			  if(send(connect_fd, "Hello,you are connected!\n", 26,0) == -1)
				  perror("send error");
			  close(connect_fd);
			  exit(0);
		  }
		  buff[n] = '\0';
		  printf("recv msg from client: %s\n", buff);
		  close(connect_fd);
	  }
	  close(socket_fd);
  }

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  /*
	File Name: client.c
  ,*/
  #include<stdio.h>
  #include<stdlib.h>
  #include<string.h>
  #include<errno.h>
  #include<sys/types.h>
  #include<sys/socket.h>
  #include<netinet/in.h>
  #include<arpa/inet.h>
  #include<unistd.h>

  #define MAXLINE 4096


  int main(int argc, char** argv) {
	  int    sockfd, n,rec_len;
	  char    recvline[4096], sendline[4096];
	  char    buf[MAXLINE];
	  struct sockaddr_in    servaddr;


	  if( argc != 2) {
		  printf("usage: ./client <ipaddress>\n");
		  exit(0);
	  }


	  if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
		  printf("create socket error: %s(errno: %d)\n", strerror(errno),errno);
		  exit(0);
	  }


	  memset(&servaddr, 0, sizeof(servaddr));
	  servaddr.sin_family = AF_INET;
	  servaddr.sin_port = htons(8000);
	  if( inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0) {
		  printf("inet_pton error for %s\n",argv[1]);
		  exit(0);
	  }


	  if( connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0) {
		  printf("connect error: %s(errno: %d)\n",strerror(errno),errno);
		  exit(0);
	  }


	  printf("send msg to server: \n");
	  fgets(sendline, 4096, stdin);
	  if( send(sockfd, sendline, strlen(sendline), 0) < 0) {
		  printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);
		  exit(0);
	  }
	  if((rec_len = recv(sockfd, buf, MAXLINE,0)) == -1) {
		  perror("recv error");
		  exit(1);
	  }
	  buf[rec_len]  = '\0';
	  printf("Received : %s ",buf);
	  close(sockfd);
	  exit(0);
  }