tcpclient.c

linux下socket网络编程实例源代码

/* Tcp client program, It is a simple example only.

 * zhengsh 200520602061 2

 * connect to server, and echo a message from server.

 */

 

 

#include <stdio.h>

#include <sys/socket.h>

#include <unistd.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <stdlib.h>

 

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

#define CLIENT_PORT ((20001+rand())%65536) // define the defualt client port as a random port

 

#define BUFFER_SIZE 255

#define REUQEST_MESSAGE "welcome to connect the server.\n"

 

void usage(char *name)

{

       printf("usage: %s IpAddr\n",name);

}

 

int main(int argc, char **argv)

{     

       int servfd,clifd,length = 0;

       struct sockaddr_in servaddr,cliaddr;

       socklen_t socklen = sizeof(servaddr);

       char buf[BUFFER_SIZE];

       

       if (argc < 2)

       {

              usage(argv[0]);

              exit(1);

       }

       

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

       {

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

              exit(1);

       }

       srand(time(NULL));//initialize random generator

       bzero(&cliaddr,sizeof(cliaddr));

       cliaddr.sin_family = AF_INET;

       cliaddr.sin_port = htons(CLIENT_PORT);

       cliaddr.sin_addr.s_addr = htons(INADDR_ANY);

 

       bzero(&servaddr,sizeof(servaddr));

       servaddr.sin_family = AF_INET;

       inet_aton(argv[1],&servaddr.sin_addr);

       servaddr.sin_port = htons(SERVER_PORT);

       //servaddr.sin_addr.s_addr = htons(INADDR_ANY);

 

       if (bind(clifd,(struct sockaddr*)&cliaddr,sizeof(cliaddr))<0)

       {

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

              exit(1);

       }

 

       if (connect(clifd,(struct sockaddr*)&servaddr, socklen) < 0)

       {

              printf("can't connect to %s!\n",argv[1]);

              exit(1);

       }

       

       length = recv(clifd,buf,BUFFER_SIZE,0);

       if (length < 0)

       {

              printf("error comes when recieve data from server %s!",argv[1]);

              exit(1);

       }

       printf("from server %s :\n\t%s ",argv[1],buf);

 

       close(clifd);

       return 0;

}