i have searched a lot for win 16 api tutorials but got only win32 api tutorials. i would like to start learning api with 16 bit and then 32. I would like to know some win16 api tutorials on web.

16-bit api functions are obsolete and were only useful on now dead MS-DOS 6.X and earlier operating systems. Don't bother with them. If you use a 32-bit compiler you can't use them anyway.

Here is a good 32-bit tutorial that you should learn.