I am new to multithreading.I understand the concepts behind it.I like
to experiment it by sample program.I decided to develop a code in which
the main thread reads a file and display it on screen continously. When
the keyboard is hit, the main thread should stop and worker thread
should write the keyboard hit char to the file.so as soon as after it
writes to the file the main thread should resume.
I like to develop it on windows environment.Please help me how to write
it.

You'll need to post to one of the Windows programming groups to get the
info you need. There are a few different libraries on threading,
depending on the compiler in use. I think posix threads have also been
ported to Windows. Again, not standard C++.