AKMA’s Random Thoughts

This back and forth is an important concept to understand in C programming, especially on the Mac's RISC architecture. Almost every variable you work with can be represented in 32 bits of memory: thirty-two 1s and 0s define the data that a simple variable can hold. There are exceptions, like on the new 64-bit G5s and in the 128-bit world of AltiVec

For this program, it was a bit of overkill. It's a lot of overkill, actually. There's usually no need to store integers in the Heap, unless you're making a whole lot of them. But even in this simpler form, it gives us a little bit more flexibility than we had before, in that we can create and destroy variables as we need, without having to worry about the Stack. It also demonstrates a new variable type, the pointer, which you will use extensively throughout your programming. And it is a pattern that is ubiquitous in Cocoa, so it is a pattern you will need to understand, even though Cocoa makes it much more transparent than it is here.

These secret identities serve a variety of purposes, and they help us to understand how variables work. In this lesson, we'll be writing a little less code than we've done in previous articles, but we'll be taking a detailed look at how variables live and work.

Being able to understand that basic idea opens up a vast amount of power that can be used and abused, and we're going to look at a few of the better ways to deal with it in this article.

But some variables are immortal. These variables are declared outside of blocks, outside of functions. Since they don't have a block to exist in they are called global variables (as opposed to local variables), because they exist in all blocks, everywhere, and they never go out of scope. Although powerful, these kinds of variables are generally frowned upon because they encourage bad program design.

When Batman went home at the end of a night spent fighting crime, he put on a suit and tie and became Bruce Wayne. When Clark Kent saw a news story getting too hot, a phone booth hid his change into Superman. When you're programming, all the variables you juggle around are doing similar tricks as they present one face to you and a totally different one to the machine.