在socket编程中，如何获取连接另一端（客户端）的ip地址，使用accept或者getpeername

//这段代码没有实际的功能，只是为了获取连接另一端的ip地址 

#include <iostream>
#include <winsock.h>
#include <stdio.h>

#pragma comment(lib, "wsock32")
using namespace std;

void main() 
{
	int ret = 0;
	WSADATA wsadata;
	WORD version = MAKEWORD(2,0);
	ret = WSAStartup(version,&wsadata);

	//服务器端口创建
	SOCKET m_hServerSocket;
	m_hServerSocket = socket(AF_INET,SOCK_STREAM,0);

	//服务器端口绑定
	SOCKADDR_IN m_addr;
	m_addr.sin_family = AF_INET;
	m_addr.sin_addr.S_un.S_addr = INADDR_ANY;//如果服务器是单网卡的，则就是这块网卡的ip地址；如果是多网卡，则是其中的任意一块的ip地址
	m_addr.sin_port = htons(10000);
	ret = bind(m_hServerSocket,(LPSOCKADDR)&m_addr,sizeof(m_addr));
	
	//服务器端口开始监听
	ret = listen(m_hServerSocket,10);//第二个参数指定最大申请的连接数

	WSADATA cli_wsadata;
	ret = WSAStartup(version,&cli_wsadata);

	//客户端端口创建
	SOCKET m_hClientSocket;
	m_hClientSocket = socket(AF_INET,SOCK_STREAM,0);


	//客户端向服务器发送连接请求
	SOCKADDR_IN m_addr1;
	m_addr1.sin_family = AF_INET;
	m_addr1.sin_addr.S_un.S_addr = inet_addr("192.168.100.57");//服务器的ip地址
	m_addr1.sin_port = htons(10000);//服务器socket的端口号
	ret = connect(m_hClientSocket,(LPSOCKADDR)&m_addr1,sizeof(m_addr1));//从客户端端口m_hClientSocket想服务器端口m_addr1发送连接请求
	
	//0xCD,0xCD,0xCD,0XCD. 因为DEBUG为每个字节初始化0xcd(204),你未正确取得对方IP，并且你的变量未初始化的结果。 
	//开始使用accept和getpeername一直返回204.204.204.204的原因

	SOCKET com_Sock;
	SOCKADDR_IN addr_conn;
	int nSize = sizeof(addr_conn);
	//initialize the memory block via the memset function
	memset((void *)&addr_conn,0,sizeof(addr_conn));

	com_Sock = accept(m_hServerSocket,NULL,NULL);			//从连接队列中取第一个连接进行通信
	//开始时候错误是因为把第三个参数写成了(int *)(sizeof(addr_conn))，所以不会报错但是取不到正确结果！！！
	//com_Sock = accept(m_hServerSocket,(SOCKADDR *)&addr_conn,&nSize); //or
	getpeername(com_Sock,(SOCKADDR *)&addr_conn,&nSize);

	char szPeerAddress[16];
	//Sets buffers to a specified character.
	memset((void *)szPeerAddress,0,sizeof(szPeerAddress));
	cout << szPeerAddress << "**************" <<endl;
	//If no error occurs, inet_ntoa returns a character pointer to a static buffer 
	//containing the text address in standard ".'' notation
	strcpy(szPeerAddress,inet_ntoa(addr_conn.sin_addr));
	//Copy a string.the second parameter strSource Null-terminated source string
	cout << szPeerAddress << endl;
	//so remember that every time use the inet_ntoa, you must copy the result by yourself
	//or it will be covered by the other value
	addr_conn.sin_addr.S_un.S_addr = inet_addr("192.168.111.2");
	cout << inet_ntoa(addr_conn.sin_addr) << endl;

	cout << endl;

}