V C++ Program for multiple color window

#include<Windows.h>
long _stdcall myfunc(HWND,UINT,UINT,long);
long _stdcall myf(HWND,UINT,UINT,long);
WNDCLASSA a;
int _stdcall WinMain(HINSTANCE i,HINSTANCE j,char *k,int l)
{
 HWND h;
 MSG m;
 a.hInstance=i;
 a.lpszClassName="my";
 a.lpfnWndProc=myfunc;
 a.hbrBackground=(HBRUSH)CreateSolidBrush(RGB(70,10,50));
 RegisterClassA(&a);
 h=CreateWindowA("my","Andrian",WS_OVERLAPPEDWINDOW,150,200,250,300,0,0,i,0);
 ShowWindow(h,l);
 a.hInstance=i;
 a.lpszClassName="mt";
 a.lpfnWndProc=myf;
 a.hbrBackground=(HBRUSH)CreateSolidBrush(RGB(100,100,250));
 RegisterClassA(&a);
 h=CreateWindowA("mt","Andrian",WS_OVERLAPPEDWINDOW,150,200,250,300,0,0,i,0);
 ShowWindow(h,l);
 while(GetMessage(&m,0,0,0))
 DispatchMessage(&m);
 return 0;
}
long _stdcall myfunc(HWND w,UINT x,UINT y,long z)
{
 switch(x)
 {
 case WM_LBUTTONDOWN:
   break;
  case WM_LBUTTONUP:
   break;
 case WM_DESTROY:
  PostQuitMessage(0);
  break;
 default:
  return DefWindowProcA(w,x,y,z);
 }
 return 0L;
}
long _stdcall myf(HWND w1,UINT x1,UINT y1,long z1)
{
 switch(x1)
 {
 case WM_LBUTTONDOWN:
   break;
  case WM_LBUTTONUP:
   break;
 case WM_DESTROY:
  PostQuitMessage(0);
  break;
 default:
  return DefWindowProcA(w1,x1,y1,z1);
 }
 return 0L;
}