how to change the bit depth of a bmp in c++

[lanse202008]

I want to chang a bmp with the bit depth of 16-bit into 8bit in c++, but I don`t know how to do.
thanks

[Peter87]

You could use some kind of library, or get to know the BMP format, read the bmp data, make the changes needed and write it back to file in the correct format.

http://en.wikipedia.org/wiki/BMP_file_format