Stereo to mono conversion

I have one stereo file with me. Here i want to convert it into mono.
Can anyone help me. how can i implement it.
Which technology i have to use.
Any sample program or link...

PLease help

What kind of file? If it's wav or some other non-compressed PCM format, you can read each sample from each channel and average the two channels into one and save it off to a mono PCM file. If it is a compressed file, you'll need to decompress to PCM first.

Sox is an open source audio toolbox so you could take a look at how they handle it if you want the details:

http://sox.sourceforge.net/