我如何检查ArrayList中的每个对象的值是否等于零？

Question

I am creating a game and need to check if all players in the playerList have played all their games. I do this by taking away from the noOfGames variable until it is 0. My problem with my code right now is that if the last player in the playerList have finished, the game ends. Here is my code:

public boolean isGameOver(){
        boolean allEqualsZero = true;

        for(Player i : playerList){
            if (i.getNoOfGames() != 0){
                allEqualsZero = false;
            }
            else{
                allEqualsZero = true;
            }
        }
        return allEqualsZero;
}

Answer 1

Your boolean variable may change for each player.

The game is over if someone has something to play, so if someone still has to play, directly return false .

If no one has something, return true at the end.

public boolean isGameOver() {
    for (Player i : playerList) {
        if (i.getNoOfGames != 0) return false;
    }
    return true;
}

---

You may otherwise use a stream if you're using java-8

public boolean isGameOver(){
    return playerList.stream()
                     .allMatch(x -> x.getNoOfGames() == 0);
}

Answer 2

The problem with this code is that it returns whether the last player equals to 0 . So what you should do, is if any one player equals to 0 return false , otherwise return true , something like that:

for(Player i : playerList){
    if (i.getNoOfGames() != 0) return false;
}
return true;

Answer 3

The easiest way to do it, is by using Java 8 Streams:

public boolean isGameOver(){
   return playerList.stream().allMatch(player -> player.getNoOfGames() == 0);
} 

allMatch will take a function that will check all the players if the number of games is 0 and return true only if all are 0.

Check the documentation for more information.