实现了标准C语言库函数printf scanf功能

				/**************标准C语言库函数的实现**********************、
				/*
				 * Printf.c
				 * Copyright (c) 2008 ,WuRen
				 * Date:2008-04-25
				 * V1.00
				*/
				#include "Printf.h"
				#include "stdlib.h"
				#include "stdio.h"
				#include "stdarg.h"
				#include "GUI.h"
				
				void Printf(char *fmt,...)
				{
					va_list arg;
					char string[256];
					va_start(arg,fmt);
					vsprintf(string,fmt,arg);
					PrintfPuts(string);
					va_end(arg);
				}
				
				void GUI_GetString(char *string)
				{
				    char *string2=string;
				    char c;
				    while((c=GUI_WaitKey())!='\r')
				    {
					if(c=='\b')
					{
					    if(	(int)string2 < (int)string )
					    {
						GUI_DispString("\b \b");
						string--;
					    }
					}
					else 
					{
					    *string++=c;
					    GUI_DispChar(c);
					}
				    }
				    *string='\0';
				    GUI_DispChar('\n');
				}