c++builder - What is the purpose of .dfm files in C++ -

i have used c++ in unix , aware of .h , .cpp files, have never worked on c++ builder , have got project contains .cpp, .h , .dfm files. the purpose of .dfm files , how use it?

thanks in advance.

dfm files describe form, , typically have associated cpp file , h file other aspects of form's class. typically edited using ide in c++ builder.