數字雨C++代碼（轉）

#include <windows.h> 

#define ID_TIMER    1 
#define STRMAXLEN  25 //一個顯示列的最大長度 
#define STRMINLEN  8  //一個顯示列的最小長度 

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; 
////////////////////////////////////////////////////////////////// 
////////////////////////////////////////////////////////////////// 
typedef struct tagCharChain //整個當作屏幕的一個顯示列,這是個雙向列表 
{ 
        struct tagCharChain *prev; //鏈表的前個元素 
        TCHAR  ch;                  //一個顯示列中的一個字符 
        struct tagCharChain *next; //鏈表的後個元素 
}CharChain, *pCharChain; 

typedef struct tagCharColumn 
{ 
        CharChain *head, *current, *point; 
        int x, y, iStrLen; //顯示列的開始顯示的x,y座標,iStrLen是這個列的長度 
        int iStopTimes, iMustStopTimes; //已經停滯的次數和必須停滯的次數,必須停滯的次數是隨機的 
}CharColumn, *pCharColumn; 

int main(HINSTANCE hInstance, HINSTANCE hPrevInstance, 
        PSTR szCmdLine, int iCmdShow) 
{ 
        static TCHAR szAppName[] = TEXT ("matrix") ; 
        HWND            hwnd ; 
        MSG            msg ; 
        WNDCLASS    wndclass ; 

        wndclass.style                = CS_HREDRAW | CS_VREDRAW ; 
        wndclass.lpfnWndProc        = WndProc ; 
        wndclass.cbClsExtra        = 0 ; 
        wndclass.cbWndExtra        = 0 ; 
        wndclass.hInstance        = hInstance ;
        wndclass.hIcon                = LoadIcon (NULL, IDI_APPLICATION) ; 
        wndclass.hCursor        = LoadCursor (NULL, IDC_ARROW) ; 
        wndclass.hbrBackground        = (HBRUSH) GetStockObject (BLACK_BRUSH) ; 
        wndclass.lpszMenuName        = NULL ; 
        wndclass.lpszClassName        = szAppName ; 

        if(!RegisterClass (&wndclass)) 
        { 
                MessageBox (NULL, TEXT ("此程序必須運行在NT下!"), szAppName, MB_ICONERROR) ; 
                return 0; 
        } 

        hwnd = CreateWindow (szAppName, NULL, 
                WS_DLGFRAME | WS_THICKFRAME | WS_POPUP, 
                0, 0, 
                GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN), 
                NULL, NULL, hInstance, 
                NULL) ; 

        ShowWindow (hwnd, SW_SHOWMAXIMIZED) ; //最大化顯示 
        UpdateWindow (hwnd) ; 
        ShowCursor(FALSE); //隱藏鼠標光標 

        srand ((int) GetCurrentTime ()) ; //初始化隨機數發生器 
        while (GetMessage (&msg, NULL, 0, 0)) 
        { 
                TranslateMessage (&msg) ; 
                DispatchMessage (&msg) ; 
        } 
        ShowCursor(TRUE); //顯示鼠標光標 
        return msg.wParam ; 
} 

TCHAR randomChar() //隨機字符產生函數 
{ 
        return (TCHAR)(rand()%2+48); //字符0或1
} 

int init(CharColumn *cc, int cyScreen, int x) //初始化 
{ 
        int j; 
        cc->iStrLen = rand()%(STRMAXLEN-STRMINLEN) + STRMINLEN; //顯示列的長度 
        cc->x = x+3 ;        //顯示列的開始顯示的x座標 
        cc->y =rand()%3?rand()%cyScreen:0; //顯示列的開始顯示的y座標 
        cc->iMustStopTimes = rand()%6 ; 
        cc->iStopTimes    = 0 ; 
        cc->head = cc->current = 
                (pCharChain)calloc(cc->iStrLen, sizeof(CharChain)); //生成顯示列 
        for(j=0; j<cc->iStrLen-1; j++) 
        { 
                cc->current->prev = cc->point; //cc->point一個顯示列的前個元素 
                cc->current->ch  = '\0'; 
                cc->current->next = cc->current+1; //cc->current+1一個顯示列的後個元素 
                cc->point          = cc->current++; //cc->point = cc->current; cc->current++; 
        } 
        cc->current->prev = cc->point; //最後一個節點 
        cc->current->ch  = '\0'; 
        cc->current->next = cc->head; 
        cc->head->prev    = cc->current; //頭節點的前一個爲此鏈的最後一個元素 

        cc->current = cc->point = cc->head; //free掉申請的內存要用current當參數 
        cc->head->ch = randomChar(); // 對鏈表頭的 元素填充 
        return 0; 
} 

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) 
{ 
        HDC          hdc ; 
        //ctn 用來確定一個顯示鏈是否 向下前進,如果等待次數超過必須等待的次數,ctn就代表要向下前進 
        int i, j, temp, ctn; //j爲一個顯示鏈中除鏈表頭外的在屏幕上顯示的y座標,temp綠色過度到黑色之用 
        static  HDC hdcMem; 
        HFONT    hFont; 
        static  HBITMAP hBitmap; 
        static  int cxScreen, cyScreen; //屏幕的寬度 高度. 
        static  int iFontWidth=10, iFontHeight=15, iColumnCount; //字體的寬度 高度, 列數 
        static  CharColumn *ccChain; 

        switch (message) 
        { 
        case WM_CREATE: 
                cxScreen = GetSystemMetrics(SM_CXSCREEN) ; //屏幕寬度 
                cyScreen = GetSystemMetrics(SM_CYSCREEN) ; 
                SetTimer (hwnd, ID_TIMER, 10, NULL) ; 

                hdc = GetDC(hwnd); 
                hdcMem = CreateCompatibleDC(hdc); 
                hBitmap = CreateCompatibleBitmap(hdc, cxScreen, cyScreen); 
                SelectObject(hdcMem, hBitmap); 
                ReleaseDC(hwnd, hdc); 
                //創建字體 
                hFont = CreateFont(iFontHeight, iFontWidth-5, 0, 0, FW_BOLD, 0, 0, 0, 
                        DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, 
                        DRAFT_QUALITY, FIXED_PITCH | FF_SWISS, TEXT("Fixedsys")); 
                SelectObject(hdcMem, hFont); 
                DeleteObject (hFont) ; 
                SetBkMode(hdcMem, TRANSPARENT); //設置背景模式爲 透明 
                iColumnCount = cxScreen/(iFontWidth*3/2); //屏幕所顯示字母雨的列數 

                ccChain = (pCharColumn)calloc(iColumnCount, sizeof(CharColumn)); 
                for(i=0; i<iColumnCount; i++) 
                { 
                        init(ccChain+i, cyScreen, (iFontWidth*3/2)*i); 
                } 
                return 0 ; 

        case WM_TIMER: 
                hdc = GetDC(hwnd); 
                PatBlt (hdcMem, 0, 0, cxScreen, cyScreen, BLACKNESS) ; //將內存設備映像刷成黑色 
                for(i=0; i<iColumnCount; i++) 
                { 
                        ctn = (ccChain+i)->iStopTimes++ > (ccChain+i)->iMustStopTimes; 
                        // 
                        (ccChain+i)->point = (ccChain+i)->head; //point用於遍歷整個顯示列 

                        //第一個字符顯示爲 白色 
                        SetTextColor(hdcMem, RGB(255, 255, 255)); 
                        TextOut(hdcMem, (ccChain+i)->x, (ccChain+i)->y, &((ccChain+i)->point->ch), 1); 
                        j = (ccChain+i)->y;  
                        (ccChain+i)->point = (ccChain+i)->point->next; 
                        //遍歷整個顯示列,將這個顯示列裏的字符從下往上顯示 
                        temp = 0 ; //temp綠色過度到黑色之用 
                        while((ccChain+i)->point != (ccChain+i)->head && (ccChain+i)->point->ch) 
                        { 
                                SetTextColor(hdcMem, RGB(0, 255-(255*(temp++)/(ccChain+i)->iStrLen), 0)); 
                                TextOut(hdcMem, (ccChain+i)->x, j-=iFontHeight, &((ccChain+i)->point->ch), 1); 
                                (ccChain+i)->point = (ccChain+i)->point->next; 
                        } 
                        if(ctn) 
                                (ccChain+i)->iStopTimes = 0 ; 
                        else continue; 
                        (ccChain+i)->y += iFontHeight; //下次開始顯示的y座標 爲當前的y座標加上 一個字符的高度 
                        //如果開始顯示的y座標減去 整個顯示列的長度超過了屏幕的高度 
                        if( (ccChain+i)->y-(ccChain+i)->iStrLen*iFontHeight > cyScreen) 
                        { 
                                free( (ccChain+i)->current ); 
                                init(ccChain+i, cyScreen, (iFontWidth*3/2)*i); 
                        } 
                        //鏈表的頭 爲此鏈表的前個元素,因爲下次開始顯示的時候 就相當與在整個顯示列的開頭添加個元素,然後在開始往上顯示 
                        (ccChain+i)->head = (ccChain+i)->head->prev; 
                        (ccChain+i)->head->ch = randomChar(); 
                } 

                BitBlt(hdc, 0, 0, cxScreen, cyScreen, hdcMem, 0, 0, SRCCOPY); 
                ReleaseDC(hwnd, hdc); 
                return 0; 

        case WM_RBUTTONDOWN: 
                KillTimer (hwnd, ID_TIMER) ; 
                return 0; 

        case WM_RBUTTONUP: 
                SetTimer (hwnd, ID_TIMER, 10, NULL) ; 
                return 0; 

                //處理善後工作 
        case WM_KEYDOWN: 
        case WM_LBUTTONDOWN: 
        case WM_DESTROY: 
                KillTimer (hwnd, ID_TIMER) ; 
                DeleteObject(hBitmap); 
                DeleteDC(hdcMem); 
                for(i=0; i<iColumnCount; i++) 
                { 
                        free( (ccChain+i)->current ); 
                } 
                free(ccChain); 
                PostQuitMessage (0) ; 
                return 0 ; 
        } 
        return DefWindowProc (hwnd, message, wParam, lParam) ; 
}