//Client side program in C/C++

#include <stdint.h>
#include <netinet/ip.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h>


using namespace std;
static void msg( const char* msg){
    fprintf(stderr, "%s\n", msg);
}

static void die(const char* msg){
    int err = errno;
    fprintf(stderr, "[%d] %s\n", err,msg);
    abort();
}

int main(){

    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if( fd < 0 ){
        die("socket()");
    }

    struct sockaddr_in addr = {};
    addr.sin_family = AF_INET;
    addr.sin_port = ntohs(1234);
    addr.sin_addr.s_addr = ntohl(INADDR_LOOPBACK);// 127.0.0.1
    int rv = connect(fd, (const struct sockaddr*)&addr, sizeof(addr));
    if( rv ){
        die("connect");
    }

    char msg[] = "hello";
    write(fd, msg, strlen(msg));

    char rbuf[64] = {};
    ssize_t n = read(fd, rbuf , sizeof(rbuf) - 1);
    if( n < 0 ){
        die("read");
    }
    printf("server says: %s\n", rbuf);
    close(fd);
    return 0;
}