linux socket如何實現服務器和客戶端對話

1.服務器端 #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 5  int main() {   struct sockaddr_in server_sockaddr,client_sockaddr;   int sin_size,recvbytes;   int sockfd,client_fd;   char buf[MAXDATASIZE]; /*創建socket*/   if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){     perror("socket");     exit(1);   }   printf("socket success!,sockfd=%dn",sockfd); /*設置服務器sockaddr_in結構*/   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); /*綁定socket和端口*/   if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1){     perror("bind");     exit(1);   }   printf("bind success!n"); /*監聽客戶端請求*/   if(listen(sockfd,BACKLOG)==-1){     perror("listen");     exit(1);   }   printf("listening....n"); /*接受客戶端請求*/   if((client_fd=accept(sockfd,(struct sockaddr *)&client_sockaddr,&sin_size))==-1){     perror("accept");     exit(1);   } /*接收客戶端信息*/   if((recvbytes=recv(client_fd,buf,MAXDATASIZE,0))==-1){     perror("recv");     exit(1);   }   printf("received a connection :%sn",buf); /*關閉socket*/   close(sockfd); } 2.客戶端 #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 100 main(int argc,char *argv[]){   int sockfd,sendbytes;   char buf[MAXDATASIZE];   struct hostent *host;   struct sockaddr_in serv_addr; /*argc<2,表示沒有輸入主機名，主機句是IP地址形式，如“192.168.1.1”*/   if(argc < 2){     fprintf(stderr,"Please enter the server's hostname!n");     exit(1);   } /*獲取主機名，地址解析函數*/   if((host=gethostbyname(argv[1]))==NULL){     perror("gethostbyname");     exit(1);   } /*創建socket*/   if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1){     perror("socket");     exit(1);   } /*設置serv_addr結構參數*/   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); /*向服務器請求連接，serv_addr是服務器端地址*/   if(connect(sockfd,(struct sockaddr *)&serv_addr,     sizeof(struct sockaddr))==-1){     perror("connect");     exit(1);   } /*發送消息給服務器，此時可以在服務器端看到"hello"字樣*/   if((sendbytes=send(sockfd,"hello",5,0))==-1){     perror("send");     exit(1);   } /*關閉連接*/   close(sockfd); }

#gcc server.c -o server #./server                       //此時服務器端在監聽 #gcc client.c -o client #./client 172.31.100.236        //客戶端向服務器端發送“hello"，服務器端監聽終止