Rock-Paper-Scissors game against computer

rock_paper_scissors.dart

void main(){
  while (true) {
    print("Rock, Paper, Scissors Shoot!");
    String playerMove = getPlayerMove();

    if (playerMove == "Quit") {
      return;
    }

    print("You played $playerMove");
    String computerMove = getComputerMove();
    print("Computer played $computerMove");
    print(whoWon(playerMove, computerMove));
  }
}
String getPlayerMove() {
  print("Would you like (R)ock, (P)aper, or (S)cissors?");
  String selection = stdin.readLineSync()!.toUpperCase();

  switch (selection) {
    case "R":
      return "Rock";

    case "P":
      return "Paper";

    case "S":
      return "Scissors";

    default:
      return "Quit";
  }
}

String getComputerMove() {
  Random rand = new Random();
  int move = rand.nextInt(3);

  switch (move) {
    case 0:
      return "Rock";

    case 1:
      return "Paper";

    case 2:
      return "Scissors";

    default:
      break;
  }
  throw Exception();
}

String whoWon(String playerMove, String computerMove) {
  if (playerMove == computerMove) {
    //if the same, it's a tie
    return "Tie";
  } else if (playerMove == "Rock" && computerMove == "Scissors") {
    return "You Win!";
  } else if (playerMove == "Scissors" && computerMove == "Paper") {
    return "You Win!";
  } else if (playerMove == "Paper" && computerMove == "Rock") {
    return "You Win!";
  } else {
    return "Computer Wins!";
  }
}