TCP/IP 소켓프로그래밍 공부 중 질문이 있습니다. 클라이언트가 서버없이도 작동하는데 어떻게 된 일이죠?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>
 
#define BUF_SIZE 1024
void ErrorHandling(char *message);
 
int main(int argc, char *argv[])
{
	WSADATA wsaData;
	SOCKET hServSock, hClntSock;
	char message[BUF_SIZE];
	int strLen, i;
 
	SOCKADDR_IN servAdr, clntAdr;
	int clntAdrSize;
 
	if(argc != 2) {
		printf("Usage : %s <port>\n", argv[0]);
		exit(1);
	}
 
	if(WSAStartup(MAKEWORD(2,2), &wsaData) != 0)
		ErrorHandling("WSAStartup() error!");
 
	hServSock=socket(PF_INET, SOCK_STREAM, 0);
	if(hServSock==INVALID_SOCKET)
		ErrorHandling("socket() error");
 
	memset(&servAdr, 0, sizeof(servAdr));
	servAdr.sin_family=AF_INET;
	servAdr.sin_addr.s_addr=htonl(INADDR_ANY);
	servAdr.sin_port=htons(atoi(argv[1]));
 
	if(bind(hServSock, (SOCKADDR*)&servAdr, sizeof(servAdr))==SOCKET_ERROR)
		ErrorHandling("bind() error");
 
	if(listen(hServSock, 5)==SOCKET_ERROR)
		ErrorHandling("listen() error");
 
	clntAdrSize=sizeof(clntAdr);
 
	for(i=0;i<5;i++)
	{
		hClntSock=accept(hServSock, (SOCKADDR*)&clntAdr, &clntAdrSize);
		if(hClntSock==-1)
			ErrorHandling("accept() error");
		else
			printf("connected client %d \n", i+1);
 
		while((strLen=recv(hClntSock, message, BUF_SIZE, 0))!=0)
			send(hClntSock, message, strLen, 0);
 
		closesocket(hClntSock);
	}
	closesocket(hServSock);
	WSACleanup();
	return 0;
}
void ErrorHandling(char* message)
{}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>
 
#define BUF_SIZE 1024
void ErrorHandling(char*);
 
int main(int argc, char *argv[])
{
	WSADATA wsaData;
	SOCKET hSocket;
	char message[BUF_SIZE];
	int strLen;
	SOCKADDR_IN servAdr;
 
	if(argc!=3) {
		printf("Usage: %s <IP> <port>\n", argv[0]);
		exit(1);
	}
 
	if(WSAStartup(MAKEWORD(2,2), &wsaData) != 0)
		ErrorHandling("WSAStartup() error!");
 
	hSocket=socket(PF_INET, SOCK_STREAM, 0);
	if(hSocket==INVALID_SOCKET)
		ErrorHandling("socket() error");
 
	memset(&servAdr, 0, sizeof(servAdr));
	servAdr.sin_family=AF_INET;
	servAdr.sin_addr.s_addr=inet_addr(argv[1]);
	servAdr.sin_port=htons(atoi(argv[2]));
 
	if(connect(hSocket, (SOCKADDR*)&servAdr, sizeof(servAdr))==SOCKET_ERROR)
		ErrorHandling("connect() error");
	else
		puts("connected.......");
 
	while(1)
	{
		fputs("Input message(Q to quit): ", stdout);
		fgets(message, BUF_SIZE, stdin);
 
		if(!strcmp(message,"q\n") || !strcmp(message,"Q\n"))
			break;
 
		send(hSocket, message, strlen(message), 0);
		strLen=recv(hSocket, message, BUF_SIZE-1, 0);
		message[strLen]=0;
		printf("message from server: %s", message);
	}
	closesocket(hSocket);
	WSACleanup();
	return 0;
}
 
void ErrorHandling(char * message)
{}