Can I display my phone screen to my tv using a cord?

Out of Curiosity wrote:

I am wondering, that without an Apple TV, I can display my phone to an ordinary TV, using a cord.

Yes.

See this -> http://www.apple.com/shop/product/MD826AM/A/lightning-digital-av-adapter

But AppleTV will do it also, in addition to doing other things.

Not without some kind of other hardware. AppleTV is the easiest and sure fire way.