修改后 简单的 TCP client

/*

 ============================================================================

 Name        : TCPclient.c

 Author      : vestinfo

 Version     : 1.1

 Copyright   : www.cnblogs.com/vestinfo

 Description : TCP client

 ============================================================================

 */



#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <stdio.h>

#include <sys/stat.h>

#include <fcntl.h>



#define PORT 8888

#define REMOTE_IP "127.0.0.1"



#define CLIENT_PORT 9999

#define CLIENT_IP "192.168.77.172"



#define MAXLENGTH 256



int main()

{

	int sockfd;

	struct sockaddr_in servaddr;

	struct sockaddr_in clientaddr;

	char mybuffer[MAXLENGTH];



	/* 创建套接字。 */

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

	{

		perror("socket");

		exit(1);

	}



	/* 绑定client的地址和端口；当然client端可不绑定，由内核分配。 */

	bzero(&clientaddr, sizeof(clientaddr));

	clientaddr.sin_family = AF_INET;

	clientaddr.sin_port = htons(CLIENT_PORT);

	clientaddr.sin_addr.s_addr = inet_addr(CLIENT_IP);

	if(bind(sockfd, (struct sockaddr *)&clientaddr, sizeof(clientaddr)) < 0)

	{

		perror("bind");

		exit(1);

	}



	/* 向server发起连接请求 */

	bzero(&servaddr, sizeof(servaddr));

	servaddr.sin_family = AF_INET;

	servaddr.sin_port = htons(PORT);

	servaddr.sin_addr.s_addr = inet_addr(REMOTE_IP);

	if(connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr))<0)

	{

		perror("connect");

		exit(1);

	}

	else

	{

		printf("connected successfully!\n");

		printf("remote ip:%s\n",REMOTE_IP);

		printf("remote port:%d\n",PORT);

	}



	for( ; ; )

	{

		bzero(mybuffer, MAXLENGTH);

		read(STDIN_FILENO, mybuffer, MAXLENGTH);		//从键盘读信息,STDIN_FILENO=0.



		if(write(sockfd, mybuffer, strlen(mybuffer)) < 0)	//发送从键盘读到的信息

		{

			perror("write");

			exit(1);

		}



		if(read(sockfd, mybuffer, MAXLENGTH) <= 0)

		{

			perror("read");

			close(sockfd);

			exit(1);

		}

		else

		{

			printf("received from server:%s\n", mybuffer);

		}

	}

	return 0;

}