在虚幻引擎射击游戏示例中的“DataType * Variable”类中是什么'类' [英] what is 'class' in 'class DataType* Variable' in Unreal Engine Shooter Game Sample

问题描述

我最近下载了Unreal 4 Engine的Shooter Game，我只是想分开c ++，但我的c ++不是最好的我注意到一个变量

I recently downloaded the Shooter Game for Unreal 4 Engine and I am just trying to pick apart the c++ but my c++ isn't the best I notice a variable called

class AShooterCharacter* MyPawn; 

在 ShooterWeapon.h

我试图理解 class 部分是什么。

I am trying to understand what the class part is.

我注意到有人拒绝了我的问题，所以我将其更改为一个问题。我希望人们愿意帮助，而不是降低我的问题。特别是在编程中

I notice people downed my question so I changed it to one question. I hope people are willing to help rather then degrade my question. Theres no such thing as a dumb question :)... Especially in programming

推荐答案

如果 AShooterCharacter 已经在范围内，那么它可能意味着基本上没有任何东西。

If AShooterCharacter is already in scope, then it probably means basically nothing.

class AShooterCharacter* MyPawn;
// ^ the same as just:
// AShooterCharacter* MyPawn;

在C中，命名结构类型时，必须使用 struct 关键字：

In C, when naming structure types, you had to use the struct keyword:

struct Foo
{
   int x, y, z;
};

struct Foo obj;

在C ++中，你不需要这样做，因为 Foo 本身就是一个可命名的类型：

In C++, you don't need to do that because Foo becomes a nameable type in its own right:

Foo obj;

但你仍然可以写 struct Foo 如果你想。

But you still can write struct Foo if you want to.

同样适用于 class 如何定义语言语法和语义。

The same applies for class, just as a consequence of how the language grammar and semantics are defined.

只有两次会产生影响。

您可以使用它来指定要引用范围内类型名称，否则会被其他一些名称，例如：

You can use it to specify that you want to refer to an in-scope type name when it is otherwise being hidden by some other name, e.g.:

class Foo {};

int main()
{
   const int Foo = 3;

   // Foo x;     // invalid because `Foo` is now a variable, not a type
   class Foo x;  // a declaration of a `Foo` called `x`;
}

但是如果你发现自己需要有更大的问题！

But if you find yourself "needing" this then, in my opinion, you have bigger problems!

否则， / p>

Otherwise, it is the same as doing this:

class Foo;   // a forward declaration
Foo* x;

可以说，如果要转发声明类型并立即声明一个指针

Arguably it saves a line of code if you are going to forward declare the type and immediately declare a pointer to an object of that type.

这是不常见的风格。

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