UE5 C++ Class Structure

Name: Cpp Class Structure
Rating: 78
Author: rickym-h

Organize your C++ classes following Unreal Engine conventions.

Module Folder Structure

code

Source/
└── ModuleName/
    ├── Public/           # Header files (.h)
    │   ├── Components/
    │   ├── Actors/
    │   └── Core/
    ├── Private/          # Source files (.cpp)
    │   ├── Components/
    │   ├── Actors/
    │   └── Core/
    └── ModuleName.Build.cs

File Naming

•No class prefix in filename: Actor.h not AActor.h
•Match filename to class name (without prefix)
•One primary class per file

Class Declaration

cpp

// HealthComponent.h
#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "HealthComponent.generated.h"

// Forward declarations (prefer over #includes)
class ABaseCharacter;
class UDamageType;

UCLASS(ClassGroup=(Custom), meta=(BlueprintSpawnableComponent))
class MYGAME_API UHealthComponent : public UActorComponent
{
    GENERATED_BODY()  // Required in all UCLASS declarations

public:
    UHealthComponent();

    // Public interface
    UFUNCTION(BlueprintCallable, Category = "Health")
    void TakeDamage(float Amount);

protected:
    virtual void BeginPlay() override;

private:
    // Private by default - enforce encapsulation
    UPROPERTY(EditDefaultsOnly, Category = "Health")
    float MaxHealth = 100.0f;

    UPROPERTY(VisibleAnywhere, Category = "Health")
    float CurrentHealth;
};

Best Practices

Practice	Reason
Forward declarations over #includes	Reduces compile times and dependencies
GENERATED_BODY() macro	Required for reflection system
Private by default	Enforce encapsulation
Split large functions	Improves compile time optimization
Don't use inline for non-trivial functions	Can increase compile times

Header Organization

cpp

#pragma once

// Engine includes
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"

// Generated header (always last)
#include "MyActor.generated.h"

// Forward declarations
class UStaticMeshComponent;

// Delegates
DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnDeathSignature);

// Class declaration
UCLASS()
class MYGAME_API AMyActor : public AActor
{
    GENERATED_BODY()
    // ...
};

Notes

•Don't worry about precompiled header setup (Unreal Build Tool handles it)
•Keep headers minimal - implementation details in .cpp files

Documentation: https://dev.epicgames.com/documentation/en-us/unreal-engine/gameplay-classes-in-unreal-engine