Noob here. I don't understand... so what happens to Objective-C? Why would you code an iOS app with one language instead of the other? Why would you use both? T

Noob here. I don't understand... so what happens to Objective-C? Why would you code an iOS app with one language instead of the other? Why would you use both? That just sounds like a pain. Is Swift the evolution of Objective-C or something?