/*
** client.c
**      Presented in COMS3200 Lecture, 19 August 2005.
**      Written by Peter Sutton.
**	improved by Wei Yin 2011
**      Compile with "gcc -o client client.c"
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <stdio.h> 
#include <unistd.h>
#include <netdb.h>
#include <string.h>
/* We ignore error handling and do not check the return values from system
** calls
*/
int main(int argc, char* argv[]) {
    int fd;
    struct in_addr* ipAddress;
    struct hostent* hostp;
    struct sockaddr_in socketAddr;
    char buffer[1024];
    int numBytes;

    int serv_port;
    if(argc!=2) {
        fprintf(stderr,"Usage: %s server_port\n", argv[0]);
	exit(1);
    }
    serv_port = atoi(argv[1]);
    if(serv_port < 1024 || serv_port > 65535) {
	fprintf(stderr, "Invalid port number: %s\n", argv[1]);
	exit(1);
    }
    hostp = gethostbyname("localhost");
    ipAddress = (struct in_addr*)hostp->h_addr_list[0];

    /* Specify the address we're going to connect to */
    socketAddr.sin_family = AF_INET;	/* Internet socket */
    socketAddr.sin_port = htons(serv_port);  /* Port number in network byte order */
    socketAddr.sin_addr.s_addr = ipAddress->s_addr;	/* Copies IP address */

    /* Create TCP socket */
    fd = socket(AF_INET, SOCK_STREAM, 0);

    /* Try to connect to our server address */
    /* Address cast to generic socket address type, but we need to specify
    ** the size of the address as the third argument */
    connect(fd, (struct sockaddr*)&socketAddr, sizeof(socketAddr));

    /* Read lines from standard input and send them to our server. Continue
    ** until standard input closes
    */
    while(fgets(buffer, 1024, stdin)) {
	write(fd, buffer, strlen(buffer));
	/* Wait for a reply */
	numBytes = read(fd, buffer, 1023);
	/* Null terminate buffer */
	buffer[numBytes] = '\0';
	/* Print out reply to standard output */
	printf("%s", buffer);
	fflush(stdout);
    }
    close(fd);
    return 0;
}