tcpip11.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define BUF_SIZE 1024
void error_handling(char * message);
int main(int argc, char * argv[])
{
	int sock;
	char message[BUF_SIZE];
	int str_len;
	struct sockaddr_in serv_adr;
	if(argc!=3)
	{
		printf("Usage :%s <IP> <port>\n", argv[0]);
		exit(1);
	}

	sock=socket(PF_INET, SOCK_STREAM,0);
	if(sock==-1)
		error_handling("socket() error");

	memset(&serv_adr,0,sizeof(serv_adr));
	serv_adr.sin_family=AF_INET;
	serv_adr.sin_addr.s_addr=inet_addr(argv[1]);
	serv_adr.sin_port=htons(atoi(argv[2]));

	if(connect(sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr))==-1)
		error_handling("connect() error!");
	else
		puts("Connected...........");

	while(1)
	{
		fputs("input message(Q to quit): ", stdout);
		fgets(message, BUF_SIZE, stdin);

		if(!strcmp(message, "q\n")||!strcmp(message,"Q\n"))
			break;
		write(sock, message, strlen(message));
		str_len=read(sock,message,BUF_SIZE-1);
		message[str_len]=0;
		printf("Message from server: %s", message);
	}
	close(sock);
	return 0;
}
void error_handling(char * message)
{
	fputs(message, stderr);
	fputc('\n', stderr);
	exit(1);
}