C# uses Microsoft .net framework Aft so yes you could compile it to different OSs but its a hassle.
C++ you would need a cross-compiler. And java you just need the Compiler in the SDK and eclipse or your IDE of chose
Also there is OpenGL for C++ it was made for C++ before beig ported to java.
C++ you would need a cross-compiler. And java you just need the Compiler in the SDK and eclipse or your IDE of chose
Also there is OpenGL for C++ it was made for C++ before beig ported to java.