How to pass in an Integer

How would I make the highlighted part an integer in order to retrieve the current round data, because right now if I make the [0] a [1] then it just loads the round 2 data, but I need it be an int so I match it to the round.

This?

public RoundData GetCurrentRoundData(int curRound)
{
  return allRoundData[curRound];
}

// or

public int CurrentRound; // track the current round
public RoundData GetCurrentRoundData()
{
  return allRoundData[CurrentRound];
}