Please explan these codes and what the commands mean

int main() { int sockfd; char buffer[MAXLINE]; char* message = "Hello Server"; struct sockaddr_in servaddr; int n, len; if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { printf("socket creation failed"); exit(0); } memset(&servaddr, 0, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_port = htons(PORT); servaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); sendto(sockfd, (const char*)message, strlen(message),0, (const struct sockaddr*)&servaddr,sizeof(servaddr)); printf("Message from server: "); n = recvfrom(sockfd, (char*)buffer, MAXLINE,0, (struct sockaddr*)&servaddr, &len); puts(buffer); close(sockfd); return 0; }