本程序vs2013 测试通过，不排除其他测试通过用例，主要是windows API的应用

#include <windows.h> #define ID_TIMER 1 #define STRMAXLEN 25 //一个显示列的最大长度 #define STRMINLEN 8 //一个显示列的最小长度 LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////// typedef struct tagCharChain //整个当作屏幕的一个显示列,这是个双向列表 {struct tagCharChain *prev; //链表的前个元素 TCHAR ch; //一个显示列中的一个字符 struct tagCharChain *next; //链表的后个元素 }CharChain, *pCharChain;typedef struct tagCharColumn{CharChain *head, *current, *point;int x, y, iStrLen; //显示列的开始显示的x,y坐标,iStrLen是这个列的长度 int iStopTimes, iMustStopTimes; //已经停滞的次数和必须停滞的次数,必须停滞的次数是随机的 }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("此程序必须运行在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); //最大化显示 UpdateWindow(hwnd);ShowCursor(FALSE); //隐藏鼠标光标 srand((int)GetCurrentTime()); //初始化随机数发生器 while (GetMessage(&msg, NULL, 0, 0)){TranslateMessage(&msg);DispatchMessage(&msg);}ShowCursor(TRUE); //显示鼠标光标 return msg.wParam;}TCHAR randomChar() //随机字符产生函数 {return (TCHAR)(rand() % (126 - 33) + 33); //33到126之间 }int init(CharColumn *cc, int cyScreen, int x) //初始化 {int j;cc->iStrLen = rand() % (STRMAXLEN - STRMINLEN) + STRMINLEN; cc->x = x + 3; cc->y = rand() % 3 ? rand() % cyScreen : 0;cc->iStopTimes = 0;cc->head = cc->current =(pCharChain)calloc(cc->iStrLen, sizeof(CharChain)); for (j = 0; j < cc->iStrLen - 1; j++){cc->current->prev = cc->point; //cc->point一个显示列的前个元素 cc->current->ch = '\0';cc->current->next = cc->current + 1; //cc->current+1一个显示列的后个元素 cc->point = cc->current++; //cc->point = cc->current; cc->current++; }cc->current->prev = cc->point; //最后一个节点 cc->current->ch = '\0';cc->current->next = cc->head;cc->head->prev = cc->current; //头节点的前一个为此链的最后一个元素 cc->current = cc->point = cc->head; //free掉申请的内存要用current当参数 cc->head->ch = randomChar(); // 对链表头的 元素填充 return 0;}LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam){HDC hdc;int i, j, temp, ctn; static HDC hdcMem;HFONT hFont;static HBITMAP hBitmap;static int cxScreen, cyScreen; //屏幕的宽度 高度. static int iFontWidth = 10, iFontHeight = 15, iColumnCount; //字体的宽度 高度, 列数 static CharColumn *ccChain;switch (message){case WM_CREATE:cxScreen = GetSystemMetrics(SM_CXSCREEN); //屏幕宽度 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);//创建字体 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); //设置背景模式为 透明 iColumnCount = cxScreen / (iFontWidth * 1 / 2); //屏幕所显示字母雨的列数 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); //将内存设备映像刷成黑色 for (i = 0; i < iColumnCount; i++){ctn = (ccChain + i)->iStopTimes++ > (ccChain + i)->iMustStopTimes;// (ccChain + i)->point = (ccChain + i)->head; //point用于遍历整个显示列 //第一个字符显示为绿 SetTextColor(hdcMem, RGB(0, 255, 0));TextOut(hdcMem, (ccChain + i)->x, (ccChain + i)->y, &((ccChain + i)->point->ch), 1);j = (ccChain + i)->y;(ccChain + i)->point = (ccChain + i)->point->next;//遍历整个显示列,将这个显示列里的字符从下往上显示 temp = 0; //temp绿色过度到黑色之用 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; //下次开始显示的y坐标 为当前的y坐标加上 一个字符的高度 //如果开始显示的y坐标减去 整个显示列的长度超过了屏幕的高度 if ((ccChain + i)->y - (ccChain + i)->iStrLen*iFontHeight > cyScreen){free((ccChain + i)->current);init(ccChain + i, cyScreen, (iFontWidth * 3 / 2)*i);}//链表的头 为此链表的前个元素,因为下次开始显示的时候 就相当与在整个显示列的开头添加个元素,然后在开始往上显示 (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;//处理善后工作 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);}