要求：1、设置电源开关键，电源打开，LED灯亮，系统开始工作；否则，系统不工作。
若电源未开，直接点击“OK”键，系统弹出错误报警对话框。
2、当电源打开后，定时器开始工作，定时间隔为1s。
每隔一秒，电表的示数增加一度。
电表示数的范围是0-20。
当示数增加到20度后，定时器关闭，电表停止不动，直至再次按下“OK”键重新计数。
3、“QUIT”按钮用于在任意时刻退出整个面板的工作。
#include <cvirte.h>#include <userint.h>#include "sfeef.h"static int panelHandle,t;double timer;int main (int argc, char *argv[]){if (InitCVIRTE (0, argv, 0) == 0)return -1; /* out of memory */if ((panelHandle = LoadPanel (0, "sfeef.uir", PANEL)) < 0)return -1;DisplayPanel (panelHandle);RunUserInterface ();DiscardPanel (panelHandle);return 0;}int CVICALLBACK QuitCallback (int panel, int control, int event,void *callbackData, int eventData1, int eventData2){switch (event){case EVENT_COMMIT:QuitUserInterface (0);break;}return 0;}int CVICALLBACK Kaishi (int panel, int control, int event,void *callbackData, int eventData1, int eventData2){switch (event){case EVENT_COMMIT:if (t == 0)MessagePopup ("错误","电源没开") ;elseSetCtrlAttribute (panelHandle, PANEL_TIMER, ATTR_ENABLED, 0);break;}return 0;}int CVICALLBACK Time (int panel, int control, int event,void *callbackData, int eventData1, int eventData2){switch (event){case EVENT_TIMER_TICK:timer++;SetCtrlVal (panelHandle, PANEL_NUMERICGAUGE, timer);if (timer==20){timer=0;SetCtrlAttribute (panelHandle, PANEL_TIMER, ATTR_ENABLED,0);}break;}return 0;}int CVICALLBACK Dianyuan (int panel, int control, int event,void *callbackData, int eventData1, int eventData2){ switch (event) { case EVENT_COMMIT: GetCtrlVal (panelHandle, PANEL_BINARYSWITCH, &t); SetCtrlVal (panelHandle, PANEL_LED, t);break;}return 0;}设计一窗口闪烁程序，使其每0.5秒闪烁一次。
