linux socket如何实现服务器和客户端对话

1.服务器端#include <sys/types.h>#include <sys/socket.h>#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <unistd.h>#include <netinet/in.h>#define SERVPORT 3333#define BACKLOG 10#define MAX_CONNECTED_NO 10#define MAXDATASIZE 5int main(){  struct sockaddr_in server_sockaddr,client_sockaddr;  int sin_size,recvbytes;  int sockfd,client_fd;  char buf[MAXDATASIZE];/*创建socket*/  if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){    perror("socket");    exit(1);  }  printf("socket success!,sockfd=%d
",sockfd);/*设置服务器sockaddr_in结构*/  server_sockaddr.sin_family=AF_INET;  server_sockaddr.sin_port=htons(SERVPORT);  server_sockaddr.sin_addr.s_addr=INADDR_ANY;  bzero(&(server_sockaddr.sin_zero),8);/*绑定socket和端口*/  if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1){    perror("bind");    exit(1);  }  printf("bind success!
");/*监听客户端请求*/  if(listen(sockfd,BACKLOG)==-1){    perror("listen");    exit(1);  }  printf("listening....
");/*接受客户端请求*/  if((client_fd=accept(sockfd,(struct sockaddr *)&client_sockaddr,&sin_size))==-1){    perror("accept");    exit(1);  }/*接收客户端信息*/  if((recvbytes=recv(client_fd,buf,MAXDATASIZE,0))==-1){    perror("recv");    exit(1);  }  printf("received a connection :%s
",buf);/*关闭socket*/  close(sockfd);}2.客户端#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <netdb.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#define SERVPORT 3333#define MAXDATASIZE 100main(int argc,char *argv[]){  int sockfd,sendbytes;  char buf[MAXDATASIZE];  struct hostent *host;  struct sockaddr_in serv_addr;/*argc<2,表示没有输入主机名，主机句是IP地址形式，如“192.168.1.1”*/  if(argc < 2){    fprintf(stderr,"Please enter the server's hostname!
");    exit(1);  }/*获取主机名，地址解析函数*/  if((host=gethostbyname(argv[1]))==NULL){    perror("gethostbyname");    exit(1);  }/*创建socket*/  if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1){    perror("socket");    exit(1);  }/*设置serv_addr结构参数*/  serv_addr.sin_family=AF_INET;  serv_addr.sin_port=htons(SERVPORT);  serv_addr.sin_addr=*((struct in_addr *)host->h_addr);  bzero(&(serv_addr.sin_zero),8);/*向服务器请求连接，serv_addr是服务器端地址*/  if(connect(sockfd,(struct sockaddr *)&serv_addr,    sizeof(struct sockaddr))==-1){    perror("connect");    exit(1);  }/*发送消息给服务器，此时可以在服务器端看到"hello"字样*/  if((sendbytes=send(sockfd,"hello",5,0))==-1){    perror("send");    exit(1);  }/*关闭连接*/  close(sockfd);}

#gcc server.c -o server#./server                       //此时服务器端在监听#gcc client.c -o client#./client 172.31.100.236        //客户端向服务器端发送“hello"，服务器端监听终止