Learn to Make iPhone Apps with Objective C for iOS7

Variables are how we store information in our apps. We use them to ask the computer to remember a date, or a number, or other information. In code, we give this data a name so we can remember it too.

Learn about the common kinds of data or types, how to create them with names or aliases, and assign an expression to this variable.

Some basic types:

• short/int/long: -1,0,1
• float/double: 3.14
• char: ‘a’, ‘b’, ‘c’
• pointers: int *(store addresses)
• struct: (x,y)

Jump into Xcode and make simple mac to learn how variables work in code.

See how to use NSLog to print out your variable as a means to checking its value. This practice will become very useful to test your apps behavior as you develop.

Create the common variable types (ints, floats, etc), perform operations on them, and see how they behave.

We need to teach our apps how to make choices. If it is rainy out, we need to bring an umbrella.

This lecture will go over logical decision making. We will cover if, else and else if statements so we can make these logic based decisions. Learn the syntax needed to implement the choices your app will need.

We will cover a new type called BOOL, boolean operators like less than or equal to, and the logical operators AND, OR, and NOT.

Create an iPhone app on the storyboard to see how decision making works in practice. design a user interface with labels and buttons. Change label text in your app when your defined conditions are met.

Practice making working iPhone apps in Xcode. Follow along to practice making and modifying variables, implementing if statements, and working with the BOOL type and logical operators.

Learning how to implement decisions is a crucial part of app development. This video will show you how to work with decision making in iPhone Apps.

Functions are the building blocks for how we get our apps to behave how we want them to. You can think of functions like the directions that come with IKEA furniture. They show you how to take all of the parts and put them together in order to build you piece of furniture.

If you had another set of the parts, you could use them again and again. Functions are the same way in that we can use the same code many times without have to rewrite it.

Learn about how functions can save you lines of code, and how their implementation works in memory with the stack frame.

Learn more about how functions work. We'll also learn more about the Xcode debugger for stepping line by line through code.

Numbers are a fundamental building block of apps. We will use them to store user data, control the components in our apps, and perform calculations.

Here we introduce the types of integers and floating-point numbers we will commonly use. We cover how they work with the NSLog function, and how we can gain access to the built in math libraries so you don’t have to write code for basic functions like sine, cosine, etc.

Common Versions of Integers:

• char
• short
• int
• long
• long long

Common Versions of Floating-point Numbers:

• float
• double

Numbers are a fundamental building block of apps. We will use them to store user data, control the components in our apps, and perform calculations.

Follow along to work with the common types of numbers and see how your apps will handle them. See how overflow errors can cause strange behavior, a good reason to choose the proper number type. We will also go over the orders of operation so you know where to put your parenthesis in your calculations.

Additionally we will cover the math libraries and special operators such as the increment and decrement operators that will save you lines of code.

Loops allow us to repeat actions multiple times. We use loops in when downloading an album of pictures from the web, when we are editing photos, or even when you are making a game and checking if a player has won yet.

Here we cover the structure of basic loops, the while and for loops. We also go into the functionality of the keywords break and continue that end the loop early or skip a particular iteration, respectively. This background will show you how to create the behavior you are looking for in a loop.

Loops allow us to repeat actions multiple times. We use loops in when downloading an album of pictures from the web, when we are editing photos, or even when you are making a game and checking if a player has won yet.

Follow along as we use a loop to reproduce the behavior we had in the countdown clock without having to use the recursive function call. Next we cover the for loop and use the debugger to see exactly what the computer is doing as it runs through our code. Lastly we add a continue call to the code so we can see its behavior with the debugger.

Pointers are a special variable type that allow us to store the memory address of another variable. This gives us access to the location of our variables while not having to hold on to them all at once, akin to having the catalog for a library instead of carrying around all of the books.

In this lecture, we introduce memory and how your computer handles it. We use this context to show how we can use pointers to store the location of variables and how we can use that to retrieve and modify them. Lastly we introduce the NULL pointer and its uses.

Pointers are a special variable type that allow us to store the memory address of another variable. This gives us access to the location of our variables while not having to hold on to them all at once. Follow along to practice creating pointers, dereferencing pointers, modifying variables via pointers, using the NULL pointer, and using the sizeof function.

Pass by reference allows us to give a function or method the address (via a pointer) to the data we want to operate on. This is especially important when dealing with large data sets like images or videos. You don’t want to have to copy an entire movie just to play it, rather, it would save time and memory to play it from its current location. Pass by reference allows us to do this.

Additionally, pass by reference allows us to modify variables within a new stack frame such as in a function or method without having to use global variables. This leads to more robustness and reusable code.

Pass by reference allows us to give a function or method the address (via a pointer) to the data we want to operate on. This is especially important when dealing with large data sets like images or videos. Follow along to see examples of Pass by Reference and pass by value.

Structures are a way to easily organize data. Instead of having separate entries for the same person, have a single contact with all the information for home number, mobile number, addresses, etc.