Please help on my win32 opengl code

#include <windows.h>
#include <gl\gl.h>
#include <gl\glu.h>

const char g_szClassName[] = "myWindowClass";

HWND		hwnd=NULL;
HINSTANCE	hInstance=NULL;
HDC			hDC=NULL;		
HGLRC		hRC=NULL;		
double		r = 0.0;

int InitGL(GLsizei width, GLsizei height)		
{
	if (height==0)		
	{
		height=1;			
	}

	glViewport(0,0,width,height);	

	glMatrixMode(GL_PROJECTION);		
	glLoadIdentity();									
	gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f); 

	glMatrixMode(GL_MODELVIEW);							
	glLoadIdentity();

	return TRUE;										
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	switch(msg)
	{
	case WM_CLOSE:
		if (hRC)											// Do We Have A Rendering Context?
		{
			if (!wglMakeCurrent(NULL,NULL))					// Are We Able To Release The DC And RC Contexts?
			{
				MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
			}

			if (!wglDeleteContext(hRC))						// Are We Able To Delete The RC?
			{
				MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
			}
			hRC=NULL;										// Set RC To NULL
		}

		if (hDC && !ReleaseDC(hwnd,hDC))					// Are We Able To Release The DC
		{
			MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
			hDC=NULL;										// Set DC To NULL
		}

		if (hwnd && !DestroyWindow(hwnd))					// Are We Able To Destroy The Window?
		{
			MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
			hwnd=NULL;										// Set hWnd To NULL
		}

		if (!UnregisterClass("OpenGL",hInstance))			// Are We Able To Unregister Class
		{
			MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
			hInstance=NULL;									// Set hInstance To NULL
		}
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	default:
		return DefWindowProc(hwnd, msg, wParam, lParam);
	}
	return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
				   LPSTR lpCmdLine, int nCmdShow)
{
	GLuint PixelFormat;
	WNDCLASSEX wc;

	MSG Msg;

	int width = 240, height = 160;

	hInstance = GetModuleHandle(NULL);

	wc.cbSize        = sizeof(WNDCLASSEX);
	wc.style         = 0;
	wc.lpfnWndProc   = WndProc;
	wc.cbClsExtra    = 0;
	wc.cbWndExtra    = 0;
	wc.hInstance     = hInstance;
	wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
	wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
	wc.lpszMenuName  = NULL;
	wc.lpszClassName = g_szClassName;
	wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

	if(!RegisterClassEx(&wc))
	{
		MessageBox(NULL, "Window Registration Failed!", "Error!",
			MB_ICONEXCLAMATION | MB_OK);
		return 0;
	}

	hwnd = CreateWindowEx(
		WS_EX_CLIENTEDGE,
		g_szClassName,
		"The title of my window",
		WS_OVERLAPPEDWINDOW & ~WS_THICKFRAME & ~WS_MAXIMIZEBOX,
		CW_USEDEFAULT, CW_USEDEFAULT, width, height,
		NULL, NULL, hInstance, NULL);

	if(hwnd == NULL)
	{
		MessageBox(NULL, "Window Creation Failed!", "Error!",
			MB_ICONEXCLAMATION | MB_OK);
		return 0;
	}

	static	PIXELFORMATDESCRIPTOR pfd=				// pfd Tells Windows How We Want Things To Be
	{
		sizeof(PIXELFORMATDESCRIPTOR),				// Size Of This Pixel Format Descriptor
			1,											// Version Number
			PFD_DRAW_TO_WINDOW |						// Format Must Support Window
			PFD_SUPPORT_OPENGL |						// Format Must Support OpenGL
			PFD_DOUBLEBUFFER,							// Must Support Double Buffering
			PFD_TYPE_RGBA,								// Request An RGBA Format
			16,											// Select Our Color Depth
			0, 0, 0, 0, 0, 0,							// Color Bits Ignored
			0,											// No Alpha Buffer
			0,											// Shift Bit Ignored
			0,											// No Accumulation Buffer
			0, 0, 0, 0,									// Accumulation Bits Ignored
			16,											// 16Bit Z-Buffer (Depth Buffer)  
			0,											// No Stencil Buffer
			0,											// No Auxiliary Buffer
			PFD_MAIN_PLANE,								// Main Drawing Layer
			0,											// Reserved
			0, 0, 0										// Layer Masks Ignored
	};

	if (!(hDC=GetDC(hwnd)))							// Did We Get A Device Context?
	{
		MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		PostMessage(hwnd,WM_CLOSE,0,0);
		return FALSE;								// Return FALSE
	}

	if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd)))	// Did Windows Find A Matching Pixel Format?
	{
		MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		PostMessage(hwnd,WM_CLOSE,0,0);
		return FALSE;								// Return FALSE
	}

	if(!SetPixelFormat(hDC,PixelFormat,&pfd))		// Are We Able To Set The Pixel Format?
	{
		MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		PostMessage(hwnd,WM_CLOSE,0,0);
		return FALSE;								// Return FALSE
	}

	if (!(hRC=wglCreateContext(hDC)))				// Are We Able To Get A Rendering Context?
	{
		MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		PostMessage(hwnd,WM_CLOSE,0,0);
		return FALSE;								// Return FALSE
	}

	if(!wglMakeCurrent(hDC,hRC))					// Try To Activate The Rendering Context
	{		
		MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		PostMessage(hwnd,WM_CLOSE,0,0);
		return FALSE;								// Return FALSE
	}


	ShowWindow(hwnd, nCmdShow);
	UpdateWindow(hwnd);

	if (!InitGL(width,height))							// Initialize Our Newly Created GL Window
	{
		PostMessage(hwnd,WM_CLOSE,0,0);
		MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
		return FALSE;								// Return FALSE
	}

	int done = false;

	while(!done)
	{
		if (PeekMessage(&Msg,NULL,0,0,PM_REMOVE))	// Is There A Message Waiting?
		{
			if (Msg.message==WM_QUIT)				// Have We Received A Quit Message?
			{
				done=TRUE;							// If So done=TRUE
			}
			else									// If Not, Deal With Window Messages
			{
				TranslateMessage(&Msg);				// Translate The Message
				DispatchMessage(&Msg);				// Dispatch The Message
			}
		}
		else
		{
			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
			glLoadIdentity();								

			// 
			glRotated(r,0,0,1);
			r+=0.1;
			glBegin(GL_TRIANGLES);					
			glVertex3f( 0.0f, 1.0f, -15.0f);		
			glVertex3f(-1.0f,-1.0f, -15.0f);		
			glVertex3f( 1.0f,-1.0f, -15.0f);		
			glEnd();		

			SwapBuffers(hDC);				
		}
		

		
	}
	return Msg.wParam;
}