初学socket，c语言写的简单局域网聊天

在客户端所在的目录新建一个IP.bwj的文件，写上服务端的IP，不要带空格，保存。双方都打开一个客户端和一个服务端就可以聊天了，（可以写自己的IP，自己跟自己聊。。）没有第三方服务器，服务端所在的电脑就是服务器。程序通过AF_INET协议族，监听7464端口，没写任何错误处理，这样便于突出主要矛盾嘛。。初学见笑。。

不知道死循环应该怎么退出，客户端可以通过输入的buffer写一个退出命令，不知道服务端怎么办，调用kbhit也不行，因为recvfrom一直在监听，我再想想。。

客户端

#include<stdio.h>
#include<winsock.h>
#pragma comment (lib,"wsock32.lib")

int main()
{
    char IPAdd[];
    FILE *readIP = fopen("IP.bwj", "r");
    fscanf(readIP, "%s", IPAdd);
    fclose(readIP);
    char buffer[];
    WSADATA data;
    WSAStartup(MAKEWORD(,), &data);
    SOCKET mySocket;
    struct sockaddr_in server;
    int len = sizeof(server);
    server.sin_family = AF_INET;
    server.sin_port = htons();
    server.sin_addr.s_addr = inet_addr(IPAdd);
    mySocket = socket(AF_INET, SOCK_DGRAM, );
    while()
    {
        scanf("%s", buffer);
        if(strcmp(buffer, "exit") == )break;
        sendto(mySocket, buffer, sizeof(buffer), ,(struct sockaddr*)&server, len);
    }
    closesocket(mySocket);
    WSACleanup();
    return ;
}

服务端

#include <stdio.h>
#include <winsock.h>
#pragma comment (lib, "wsock32.lib")
int main()
{
    char buffer[];
    WSADATA data;
    WSAStartup(MAKEWORD(,), &data);
    SOCKET mySocket;
    struct sockaddr_in local;
    struct sockaddr_in from;
    local.sin_family = AF_INET;
    local.sin_port = htons();
    local.sin_addr.s_addr = INADDR_ANY;
    mySocket = socket(AF_INET, SOCK_DGRAM, );
    bind(mySocket, (struct sockaddr*)&local, sizeof(local));
    int len = sizeof(from);
    while()
    {
        recvfrom(mySocket, buffer, sizeof(buffer), , (struct sockaddr*)&from, &len);
        printf("Received from %s :\n%s\n", inet_ntoa(from.sin_addr), buffer);
    }
    closesocket(mySocket);
    WSACleanup();
    return ;
}