#include "windows.h"

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
HINSTANCE hInst;
LPCSTR AppName = "MyProgramm";

int WINAPI WinMain(HINSTANCE hInstance, 
				   HINSTANCE hPrevInstanse, 
				   LPSTR lpCmdLine, int nShowCmd){

	HWND hWnd;
	MSG msg;
	hInst = hInstance;

	WNDCLASS wc;
	ZeroMemory(&msg,sizeof(wc));
	wc.style = CS_HREDRAW|CS_VREDRAW;
	wc.lpfnWndProc = (WNDPROC)WndProc;
	wc.hInstance = hInst;
	wc.hIcon = LoadIcon(hInst,IDI_APPLICATION);
	wc.hCursor = LoadCursor(NULL,IDC_ARROW);
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+ 1 );
	wc.lpszClassName = AppName;

	RegisterClass(&wc);

	hWnd = CreateWindow(AppName,AppName,WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,
						 0 , 300 , 300 ,NULL,NULL,hInst,NULL);

	ShowWindow(hWnd,SW_SHOW);
	UpdateWindow(hWnd);

	while(GetMessage(&msg,NULL, 0 , 0 )){
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	LRESULT CALLBACK WndProc(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam){

		switch(msg){
		case WM_DESTROY:
				PostQuitMessage( 0 );
				break;
		default:
			return DefWindowProc(hWnd,msg,wParam,lParam);
		}

		return  0 ;
	}

Compiling...
main.cpp
D:\C++\Win\W1\main.cpp( 38 ) : error C2601: 'WndProc' : local function definitions are illegal
D:\C++\Win\W1\main.cpp( 51 ) : fatal error C1004: unexpected end of file found
Error executing cl.exe.

W1.exe -  2  error(s),  0  warning(s)

Compiling...
main.cpp
D:\C++\Win\W1\main.cpp( 38 ) : error C2601: 'WndProc' : local function definitions are illegal
D:\C++\Win\W1\main.cpp( 50 ) : warning C4508: 'WinMain' : function should return a value; 'void' return type assumed
Error executing cl.exe.

W1.exe -  1  error(s),  1  warning(s)

Compiling...
main.cpp
D:\C++\Win\W1\main.cpp( 38 ) : error C2601: 'WndProc' : local function definitions are illegal
Error executing cl.exe.

W1.exe -  1  error(s),  0  warning(s)