如何在视图控制器之间传递变量？

i'm having a hard time with Xcode; for some reason, it just won't let me pass a variable from one view controller class to another. It should work, i was basically just copying/pasting from my other classes (it works on all of them... except this one). I've been at it all night long, tried everything i could think of and still it remains.i'm having a hard time with Xcode; for some rea