用API函数编写一个键盘处理程序，要求在窗口中绘制一个矩形，大小与颜色自己确定，当按光标键时，矩形能够随之移动，若按字符键时能够将按键的字符写在矩形中，写满自动清空。-used to prepare an API function keyboard handling procedures, requirements in the window drawing a rectangle, Size and color set ourselves that if the cursor keys, will be moved to rectangular, According to Key characters will be able to switch characters written on the rectangular, written all over automatically emptied.