// a->客户端
#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>

int main(int argc, char const *argv[])
{
    int a_fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (a_fd < 0)
    {
        perror("socket");
        return 1;
    }

    struct sockaddr_in addr;
    bzero(&addr, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(8000);
    addr.sin_addr.s_addr = inet_addr("127.0.0.1"); // 服务器在本地

    while (1)
    {
        char buf[1] = "";
        bzero(&buf, sizeof(buf));
        scanf("%s", buf);
        sendto(a_fd, buf, strlen(buf), 0, (struct sockaddr *)&addr, sizeof(addr));

        char recvbuf[128] = "";
        socklen_t addr_len = sizeof(addr);
        recvfrom(a_fd, recvbuf, strlen(recvbuf), 0, (struct sockaddr *)&addr, &addr_len);
        printf("%s", recvbuf);

        if (strncmp(recvbuf, "bye", 3) == 0)
            break;
    }

    close(a_fd);

    return 0;
}