Fell in love with coding

I'm a graduating senior who majors in Business at a top school. Recently, I've branched out of my comfort zone and have taken some courses in C++. I I've done really well in the intro courses and I regret not doing a dual major in BBA/CS!

I have a job lined up at a top consulting firm after graduation however I still want to code. Any advice on the best plan of attack? My goal is to build an iOS app. Should I just pick up a book on Objective-C? I can't imagine learning coding by reading a book…I appreciate any tips!