All you people that don't care for C#, please just stop and learn about the subject before talking about it. And enough of the nonsense that C# is not portable.... As long as you avoid using any OS specific code from the .NET framework you will have no problem moving your program to a different platform. The same applies to C++.
Just because you do not use something does not mean there is something wrong with it or can't be considered as a perfectly valid alternative to something else. Please note I do use C++ also.
As for compiling, no language that utilizes the CLI (C#, VB.NET, F#, ect) is ever compiled to native code until it is ran. This means you can compile a C# program with Visual Studio, switch over to linux and drop that same executable into mono and it will still run without the need for recompilation.
Concerning the porting, do use C# since it's microsoft only
Of you are using C# its gonna be much harder, because C# and .NET is meant for Windows
So untrue, just because Microsoft designed the language doesn't make this the case. It is like saying the entire linux kernel or git was designed exclusively for Linus Torvald's personal use. C# is in fact a ISO and ECMA standard language and was designed to be implemented cross platform. I don't think that all the MS specific stuff that was dropped into C++ was an ISO standard.
So lets say i`ll stick with C#.If i want to deploy it to Mac or Linux the only thing i need its Mono and the OSs installed on my computer and maybe Wine to be sure that i`ll work perfectly ?? I`m asking this because i really want to participate in the next Ludum Dare competition and i need to port the games on all 3 OSs whitout any problems
You won't even need Wine, as long as you avoid the very few windows specific namespaces in the .NET framework all you need to do is remap the CSFML dlls to the platform specific naming. Then your program will run without any problem on any platform using mono.
On a side note, Murii if you are looking at participating in the game jam (and I highly recommend that you do) I have ported Thor to C# with my NetEXT library. It contains many helpful classes that should help get you off the ground when you are writing your game.