Forward Declaration Question

[tctoki]

class UCapsuleComponent;


UCLASS()
class TOONTANKS_API APawnBase : public APawn
{
	GENERATED_BODY()

private:

	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Components", meta=(AllowPrivateAccess = "true"))
	UCapsuleComponent* CapsuleComp;
	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Components", meta=(AllowPrivateAccess = "true"))
	UStaticMeshComponent* BaseMesh;
	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Components", meta=(AllowPrivateAccess = "true"))
	UStaticMeshComponent* TurretMesh;
	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Components", meta=(AllowPrivateAccess = "true"))
	USceneComponent* ProjectileSpawnPoint;


public:
	// Sets default values for this pawn's properties
	APawnBase();
	
};

In PawnBase.h, we have UCapsuleComponent and UStaticMeshComponent and USceneComponent, I wonder why we only have UCapsuleComponent class in the forward declaration, and no need to declare for the other two class?

Thanks in advance!

[Aryan_Kumar]

You can either have a class in forward declaration or you can simply #include the header file of the class -

class UCapsuleComponent;

Or,

#include "Components/CapsuleComponent.h"
// Components/CapsuleComponent.h is the path of the class.

Both methods will work just fine.

So, I haven’t done this Toon tanks section, but I think the instructor, instead of forward declaring, he just #included the path of the class.

[tctoki]

Thanks for your reply!
I wonder why we only need to declare the UCapsuleComponent but don’t need to declare the other two, USceneComponent and UStaticMeshComponent?

[Aryan_Kumar]

I haven’t seen the instructor’s source code. Maybe he just #included the path of the class in the header file. That’s the alternate way of doing this. You can either forward declare or #include the path of the class. Either way will work just fine.

[tctoki]

He didn’t include in cpp file and also didn’t forward declare it in header file. He only include the capusleComponent.h in cpp file.

[DanM]

It would come from one of the includes that are already there.

[tctoki]

Do UStaticMeshComponent and USceneComponent come from #include “GameFramework/Pawn.h”?
How can I know if it comes from the include?

[DanM]

Do UStaticMeshComponent and USceneComponent come from #include “GameFramework/Pawn.h”?

I don’t know, there’s too many includes. But it has to come in somewhere otherwise it wouldn’t compile.