unreal4 dynamic 2d tarray

WorldGen.h
#pragma once

#include "Tile.h"
#include "GameFramework/Actor.h"
#include "WorldGen.generated.h"

UCLASS()
class SNEAKYSNAKE_API AWorldGen : public AActor
{
    GENERATED_BODY()

public:
    // Sets default values for this actor's properties
    AWorldGen();

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

    // Called every frame
    virtual void Tick( float DeltaSeconds ) override;

    UPROPERTY(EditAnywhere)
        FVector2D size;
    UPROPERTY(EditAnywhere)
        int splits;
    UPROPERTY(EditAnywhere)
        int doors;
private:
    TArray<TArray<ATile>> levelMap;
};
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worldgen.cpp
#include "SneakySnake.h"
#include "WorldGen.h"
#include "Tile.h"

// Sets default values
AWorldGen::AWorldGen()
{
    // Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = true;
}

// Called when the game starts or when spawned
void AWorldGen::BeginPlay()
{
    Super::BeginPlay();

    TArray<ATile> row;
    for (int j = 0; j < size.X; j++) {
        for (int k = 0; k < size.Y; k++) {
            row.Add(ATile(j, k));
        }
        levelMap.Add(row);
    }
    //UE_LOG(LogTemp, Warning, TEXT("tile exists at %d, %d"), levelMap[size.X - 1][size.Y - 1].position.X, levelMap[size.X - 1][size.Y - 1].position.Y);
}

// Called every frame
void AWorldGen::Tick( float DeltaTime )
{
    Super::Tick( DeltaTime );
}
______________________________________________
tile.h
#pragma once

#include "GameFramework/Actor.h"
#include "Tile.generated.h"

UCLASS()
class SNEAKYSNAKE_API ATile : public AActor
{
    GENERATED_BODY()

public:
    // Sets default values for this actor's properties
    ATile();
    ATile(int,int);

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

    // Called every frame
    virtual void Tick( float DeltaSeconds ) override;

    FVector position;
};
_______________________________________________
tile.cpp
#include "SneakySnake.h"
#include "Tile.h"

// Sets default values
ATile::ATile()
{
    // Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = true;
}

ATile::ATile(int x, int y)
{
    // Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = true;
    position.X = x;
    position.Y = y;
}

// Called when the game starts or when spawned
void ATile::BeginPlay()
{
    Super::BeginPlay();
}

// Called every frame
void ATile::Tick( float DeltaTime )
{
    Super::Tick( DeltaTime );
}