A reply to stackoverflow #67718153: "Bool array transfer from server with UDP in C"

net.c

/* in reply to https://stackoverflow.com/questions/67718153/bool-array-transfer-from-server-with-udp-in-c */
/* compile: cc net.c -o net */
/* run (twice): ./net & ./net 127.0.0.1 */
#include <stdbool.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>

int main(int argc, char** argv){
    int sock;
    struct sockaddr_in addr;
    socklen_t addrlen;
    struct hostent* peer;
    char netbuf [512]; /* use 8bit cell to store a boolean, for convenience */

    sock = socket(PF_INET, SOCK_DGRAM, 0);
    addrlen = sizeof(addr);
    memset(&addr, 0, addrlen);
    addr.sin_family = PF_INET;
    addr.sin_port = htons(5000);

    if (argc == 1) {
        bind(sock,(struct sockaddr*)&addr,addrlen);
        addr.sin_addr.s_addr = htonl(INADDR_ANY);
        recvfrom(sock, netbuf, sizeof(netbuf), 0, 
                (struct sockaddr*)&addr, &addrlen);

        for (int i = 0; i < 512; i++) {
            printf("%d, ", netbuf[i] ? 1 : 0);
        }

        printf("\n");

        sendto(sock, "ok", sizeof("ok"), 0, 
                (struct sockaddr*)&addr, addrlen);
    } else {
        peer = gethostbyname(argv[1]);
        memmove(&addr.sin_addr.s_addr,
                peer->h_addr,peer->h_length);
#if 0
        /* no need to connect with UDP */
        connect(sock, (struct sockaddr*)&addr, addrlen);
#endif
        for (int i = 0; i < 512; i++) {
            /* alternate true and false */
            netbuf[i] = i % 2;
        }

        sendto(sock, netbuf, 512, 0, 
                (struct sockaddr*)&addr, addrlen);

        recvfrom(sock, netbuf, sizeof(netbuf), 0,
                (struct sockaddr*)&addr, &addrlen);
        printf("%s\n", netbuf);
    }
    close(sock);
    exit(EXIT_SUCCESS);
}