请问如何将这段C代码改成基于对话框的VC程序？

因为对VC不熟，现在需要将这段C代码改成基于对话框的VC工程，
C代码如下：
C/C++ code:

#include <windows.h>
#include <time.h>
const int ScrnWidth=1024;
const int ScrnHight=768;
const long SnowCol =0xFEFFFE;
const long SnowColDown =0xFFFFFF;
const long SnowColDuck =0xFFDDDD;
const int SnowNum = 400;
const int ID_TIMER = 1;

const char g_szClassName[] = "myWindowClass";

typedef struct POINTAPI
{
long x;
long y;
} a;

static HDC hDC1;
static struct POINTAPI pData[500];
static long pColor[500];
static int Vx,Vy,PVx,PVy,timecont;

long Abs(long num)
{
if(num>=0)return(num);
else return(-num);
}

int Random(int max)
{
return(rand()%max);
}

void InitP(int i)
{
pData[i].x=Random(ScrnWidth);
pData[i].y = Random(5);
pColor[i] = GetPixel(hDC1, pData[i].x, pData[i].y);
}

long GetContrast(int i)
{
long ColorCmp;
long tempR;
long tempG;
long tempB;
int Slope;

if(PVy!=0) Slope = PVx / PVy;
else Slope = 2;

if(Slope==0) ColorCmp = GetPixel(hDC1, pData[i].x, pData[i].y + 1);
else if(Slope > 1) ColorCmp = GetPixel(hDC1, pData[i].x + 1, pData[i].y + 1);
else ColorCmp = GetPixel(hDC1, pData[i].x - 1, pData[i].y + 1);

if(ColorCmp==SnowCol)return 0;