Few Questions about Programming Quick Start

Development Programming & Scripting
1

I have made it works according to the guide (Unreal Engine CPP Quick Start | Unreal Engine 5.2 Documentation). Thanks for the guide. Though I have few questions about the code:

float RunningTime;

void AFloatingActor::Tick( float DeltaTime )
{
   Super::Tick( DeltaTime );

   FVector NewLocation = GetActorLocation();
   float DeltaHeight = (FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(RunningTime));
   NewLocation.Z += DeltaHeight * 20.0f;       //Scale our height by a factor of 20
   RunningTime += DeltaTime;
   SetActorLocation(NewLocation);
 }
  1. Why declear the “float RunningTime” in the .h file rather than .cpp file?
  2. What DeltaTime means here?
  3. What FMath::Sin means?
  4. What Super::Tick( DeltaTime ); means here?

Thanks a lot!

2
  1. Readability, Transparency and compiling time + standarisation
  2. The time the last frame took to be drawn. If you are playing at 60 FPS, 1/60 ~ 0.016 seconds
  3. Sin function, check basic trigonometry on google
  4. The call to the parent tick function - see inheritance -

As a recommendation i would suggest you to learn C++ before engaging with the UE4 API