Good questions, keep them coming!
Keep at it. There's a lot going on, a lot to learn. You will get frustrated, but that's OK.
My problem with going strait to a GUI is I have hard time finding error. not knowing where things are going wrong during a program can be extremely frustrating.
I'm not arguing with you for the sake of arguing, but I don't see how going to the GUI makes it harder to find any errors. If you start with a tutorial GUI app, there won't be any GUI related errors. Also, the effort to get the command line app to recognize separate inputs equals the effort to get the GUI app to work.
I don't see the benefit of starting with a command line app as opposed to a GUI app.
I looked for a calc app but they all seem to be Xcode 3. Do you know of any good tutorials for x-code 4 on calculators?
Googled "Xcode 4 tutorial" and the fourth results was "Xcode 4 Tutorial Basic Calculator" at
http://www.youtube.com/watch?v=Ihw0cfNOrr4. I haven't watched it, but it's 20 minutes long and it seen very detailed from my five-second glance at it.
If that doesn't work, head back to google. I suggested a calculator app because that takes in numbers and does calculations on them, which is what you want to do. Once you get the calculator app going, you can implement your app by changing the "plus" function to "translate-temperature-differential-to-BTU".
What I mean by "math handling" is knowing how to build an equation so that it works in Xcode. Like right now most of my stuff is handled inside of excel or numbers. this is getting very old and very clunky. I just need to see how the syntax works. I'm learning fast.
I think you're talking about syntax (how to express what you want to do in a format that the objective-c understands). You'll pick that up as you walk through the tutorial. There are two types of syntax in objective-c:
1. The normal C syntax, where a formula may look like:
(variable name) = (some constant) * (another variable name)
for example
britishThermalUnitsPerHour = 500 * gallonsPerMinute
* (temperatureFinalInCelcius -temperatureInitalInCelcius)
2. Method messaging syntax
(variable name) = [(object) (message)];
for example
NSString * myName;
myName = [[NSString alloc] init];
myName = @"PatrickCocoa";
Note the verbosity of my variable names. Your code has a variable "BTU" which it turns out is NOT British Thermal Units, but is BTUs per hour. That is misleading and will cause confusion (I originally had my variable name as "britishThermalUnits" until I happened to take another look at your original code. If you're programming in a team, misleading variable names will quickly get you ostracized. If you're not programming in a team, then six-months-from-now-dieseltwitch will thank current-dieseltwitch. Believe me.