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;
}