Do all countries use Generally Accepted Accounting Principles (GAAP) or is is used only by U.S. companies?

Not all countries use GAAP.
Many develpoed countries do.
Australia certainly does.
There are some European Countries
That are way ahead of GAAP.
This by definition makes them well ahead of the US , some of them like THE NEDERLANDS
Are ahead by about 100 years.

Dual concept

Huma, please start your own thread instead of piggy-backing onto something several months old that isn't even related.

Also, if you want help, you need to actually ask something, and be specific about what you're referring to. (i.e. dual concept of WHAT? Little out of context)