error: expected identifier before numeric constant

当有下列语句时将出现此状况

 printf("\n\t\tSales as percentage of inventory:\t\t%f".\
	     100*((float)total_cars_sold[brand]/(float)
		  cars_in_stock[brand]));

57:7: error: expected identifier before numeric constant

原因是\前的不是,  误写成了. 

网上查了下还有相关 的也出现了此类问题：

http://hi.baidu.com/yesbaba/blog/item/a8df963613c96c350a55a95b.html