此代码用于实现BMP24位图的压缩，简单易懂，操作简便。-This code is used to implement the BMP24 bitmap compression, easy to understand, easy to operate.

将*.bmp24位真彩图转化为*.bmp8位灰度图，纯C++程序编写-* .bmp24 Bit true color images will be converted to* .bmp8 bit grayscale, pure C++ programming