In which language application program is written?

Please clarify your question! "Language application program" is quite broad.

To help me answer, please specify:

* What kind of application program are you referring to? For example:

* A web browser (like Chrome, Firefox, Safari)

* A word processor (like Microsoft Word, Google Docs)

* A game (like Minecraft, Fortnite)

* A specific program you have in mind

* Are you asking about the programming language used to write the program's core logic? Or are you asking about the language used for its user interface, or its scripting language?

Once you give me more information, I can provide a more accurate answer.