说明：  应用于51的浮点数计算器程序，其中键盘的扫描程序需自己写（我不想让人都懒起来），还有就是LCD显示部分，根据情况更改
(applied to the float 51 calculator program, the keyboard scan process required to write their own (I do not want to have lazy up), the LCD display is also part of the changes under)