onoverlapbegin ue4 c++

...
void AUnrealCPPCharacter::OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
	if (OtherActor && (OtherActor != this) && OtherComp) 
	{
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Overlap Begin"));
	}
} 

void AUnrealCPPCharacter::OnOverlapEnd(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex)
{
	if (OtherActor && (OtherActor != this) && OtherComp) 
	{
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Overlap End"));
	}
}

public
  ...

  // declare overlap begin function
	UFUNCTION()
	void OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);

	// declare overlap end function
	UFUNCTION()
	void OnOverlapEnd(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex);

void ALightSwitchCodeOnly::OnOverlapBegin(UPrimitiveComponent* OverlappedComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)  
{  
    // Other Actor is the actor that triggered the event. Check that is not ourself.  
    if ( (OtherActor != nullptr ) && (OtherActor != this) && ( OtherComp != nullptr ) )  
    {  
        // Turn off the light  
        PointLight->SetVisibility(false);  
    }  
}

AUnrealCPPCharacter::AUnrealCPPCharacter()
{
  ...

  // declare overlap events
	TriggerCapsule->OnComponentBeginOverlap.AddDynamic(this, &AUnrealCPPCharacter::OnOverlapBegin); 
	TriggerCapsule->OnComponentEndOverlap.AddDynamic(this, &AUnrealCPPCharacter::OnOverlapEnd); 

}