Forward declaration issues

Development Programming & Scripting
1

Hi there,

I’ve read Rama’s post on forward declarations but am having an issue I think I’m completely missing a basic fundamental here and I’m probably doing this the wrong way, any help would be much appreciated:

I have two classes:

AFood (APawn)
AHero (ACharacter)

in AHero I want a list of food in the players view, then for each food item I want them to move(I know how crazy this probably sounds from a game design perspective but please bear with me!). In both classes I want to cast to the specific class and use functions from both, here’s what I have:

AHero.h

GENERATED_BODY()
class AFood;

...

protected:
TArray<AFood*> VisibleFood;

AHero.cpp

#include "TheFoodGame.h"
#include "Hero.h"
#include "Food.h"

AHero::AHero()

...

void AHero::CheckFood()
{
    TTransArray<AActor*> AllActors = GetWorld()->PersistentLevel->Actors;

    for (AActor* CurrentActor : AllActors)
    {

        if (CurrentActor != nullptr && Cast<AFood>(CurrentActor)) {
            AFood* CastedActor = Cast<AFood>(CurrentActor);

            FVector CurrentActorLocation = CurrentActor->GetActorLocation();
            FVector OurLocation = GetActorLocation();
            FVector OurForwardVector = GetActorRotation().Vector();

            FVector TempVec = CurrentActorLocation - OurLocation;
            TempVec.Normalize();

            float DotProduct = FVector::DotProduct(OurForwardVector, TempVec);

            if (DotProduct > 0.7f) {
                VisibleFood.Add(CastedActor);
            }
        }

    }
}

That will give me an “use of undefined type ’ AHero::AFood’” error as is, removing the #include on the cpp doesn’t change this. this is before attempting to do anything with “CastedActor”, Ideally I’ll like to call CastedActor->MoveFood(); which would in AFood::MoveFood(); cast the player to AHero for some information and then move to it. using just includes however would net me circular dependencies.

2

It looks like you’re doing the forward declaration inside AHero’s class declaration; it should go outside it (so before the UCLASS macro). Doing it inside AHero’s declaration makes the compiler think it’s a class inside AHero’s scope (hence AHero::AFood instead of it just saying AFood).

3

That was it, thank you very much!