Structures - Arrow or Dot? tutorial

[page=Introduction]
Hello again!

This tutorial will teach you a bit about structures and how they are used. I barely know anything about how C++ works, or how C works actually, I am just a modder, I don't work with Windows apps (not yet atleast, I am in the progress of one..).

Alright, the main purpose was for structures. Every structure needs to be linked together with another structure to make a pointer (either seen as an arrow -> or a dot .), such as (Quake2) ent->client, or ent->client->resp.

Now, you can use either, but you can use them in different ways to make them better.

[page=Simple Structures]
Here's an example of a simple structure.

struct teststruct
{
	int test1;
	float test2;
	BOOL test3;
};

As you can see, this structure is pretty much nothing. It can be used for like a character settings, like so:

struct character
{
	int age;
	int height;
	int weight;
	char *name;
	char *ally;
};

Let's go to the next page, to learn about Arrow pointers!

[page=Arrow Pointers]
Arrow Pointers. These are usually used the most in engines or very important structures.
Main structures usually are linked with arrows.

Here is an example of the character one, but with an arrow pointer:

First, we need to add this new structure above the character one:

struct character_build
{
	int height;
	int weight;
};

Now, let's edit our character structure to fit this.

struct character
{
	int age;
	struct character_build *char_build;
	char *name;
	char *ally;
};

Now, let's make a function to go with this.

void SetCharAge (character *charac)
{
	charac->age = 21;
	charac->char_build->height = 8.3;
	charac->char_build->weight = 180;
}

That will set those to the specified numbers.
Next page, let's learn when and when not to use dot pointers!

[page=Dot Pointers]
Dot pointers are like arrow pointers, but are usually used for stuff less important.

Now, let's say we want a new structure thing for effects. (It's not real code though..) Let's try this. In your opinion, which will use a dot; effects, or the char_build?

typedef struct
{
	int r;
	int b;
	int g;
} color_s;

There is a struct with three colors. Of course they are just ints, but oh well.

struct effect_s
{
	color_s flash;
	color_s muzzle_color;
};

There is the effects struct. It makes dot references to color_s.

typedef struct
{
	int height;
	int weight;
	int bounding_box[3];
} character_build;

I added one new part to this. It's an array for a bbox. I recommend using vectors with a 3D engine, not an int ;)

struct character
{
	int age;
	character_build char_build;
	char *name;
	char *ally;
	struct effect_s *effects;
};

Here's the heart of the code.
Now, what happens here is this.

It first knows char_build, and knows it's a dot pointer now, so you will use it as so:

character->char_build.height = 8.3;

for example.

Now, the effects works a bit different.

character->effects->flash.r = 8.44;

Personally, I use arrow pointers to lead to a structure with more structures, while using dot pointers for structures with only variables and ints.

[page=How to make them?]

Now, you're wondering, How do I make arrow/dot pointers, and what's the difference in the codes? Well, here's how you do it.

Arrow pointers:

struct structure_name
{
	<<code stuff here>>
}

Dot pointers:

typedef struct
{
	<<code stuff here>>
} structure_name;

Linking them;

Arrow pointers:

struct structure_name *linked_name;

Dot pointers:

structure_name linked_name;

the structure_name in linking is the name of the struct.
The linked_name can be different. It is used in the final structure, such as:

char-> |-----------------|
| linked_name |
|-----------------|

[page=Conclusion]

Hope you learned something. That's my aim!
Later everyone!

-Paril Kalashnikov