uwp print to console
You can use Debug.WriteLine() method from System.Diagnostics namespace
https://msdn.microsoft.com/en-us/library/system.diagnostics.debug.writeline%28v=vs.110%29.aspx
When you start debugging your application those messages will be displayed in the Output Window (Standard VS shortcut is Ctrl+Alt+O, ReSharper shortcut is Ctrl+W, O)