It is not possible to trade with one line coding.
However, there are options to trade without visiting any exchange. Personally, I prefer trading via OTC with allow me to be connected with other buyers/sellers directly without any need of joining an exchange and pay high fees for that.
Well, well, now if you become a buyer and buy through OTC, will you just trust the seller? I think here the role of the exchange is very important to maintain the security of your trade compared to through the OTC market.
That is why there should be a third party involvement like exchanges for security purposes. Yes, fees are quite high especially in btc. Except if you don't want fees to pay, directly transactions is another choice. Like trading btc and do some transactions directly with acquintances or people you may know. In that case, both security and the fees are already solved.