请你基于 Arduino UNO控制器设计一个4人 抢答器系统，具体要求如下。 2.设计要求： 当按下开始按键后开始抢答; (2）在开始按键后 4个抢答按键中首先按下的按键即为 抢答成功的选手，此时通过串口通信输出该选手的号码 并且该选手对应的LED灯点亮，后续再抢答的选手无效（3）当按下复位按键后上次抢答结束并进入下一次抢答的等待状态;给出arduino设计程序并对代码进行解释

以下是一个基于Arduino UNO控制器的4人抢答器系统的设计程序：

const int startButtonPin = 2;
const int resetButtonPin = 3;
const int player1ButtonPin = 4;
const int player2ButtonPin = 5;
const int player3ButtonPin = 6;
const int player4ButtonPin = 7;

const int player1LedPin = 8;
const int player2LedPin = 9;
const int player3LedPin = 10;
const int player4LedPin = 11;

int player1Pressed = 0;
int player2Pressed = 0;
int player3Pressed = 0;
int player4Pressed = 0;

int currentPlayer = 0;

void setup() {
  pinMode(startButtonPin, INPUT);
  pinMode(resetButtonPin, INPUT);
  pinMode(player1ButtonPin, INPUT);
  pinMode(player2ButtonPin, INPUT);
  pinMode(player3ButtonPin, INPUT);
  pinMode(player4ButtonPin, INPUT);

  pinMode(player1LedPin, OUTPUT);
  pinMode(player2LedPin, OUTPUT);
  pinMode(player3LedPin, OUTPUT);
  pinMode(player4LedPin, OUTPUT);

  Serial.begin(9600);
}

void loop() {
  if (digitalRead(startButtonPin) == HIGH) {
    currentPlayer = 0;

    while (currentPlayer == 0) {
      if (digitalRead(player1ButtonPin) == HIGH && player1Pressed == 0) {
        currentPlayer = 1;
        player1Pressed = 1;
        digitalWrite(player1LedPin, HIGH);
        Serial.println("Player 1 pressed first!");
      }
      if (digitalRead(player2ButtonPin) == HIGH && player2Pressed == 0) {
        currentPlayer = 2;
        player2Pressed = 1;
        digitalWrite(player2LedPin, HIGH);
        Serial.println("Player 2 pressed first!");
      }
      if (digitalRead(player3ButtonPin) == HIGH && player3Pressed == 0) {
        currentPlayer = 3;
        player3Pressed = 1;
        digitalWrite(player3LedPin, HIGH);
        Serial.println("Player 3 pressed first!");
      }
      if (digitalRead(player4ButtonPin) == HIGH && player4Pressed == 0) {
        currentPlayer = 4;
        player4Pressed = 1;
        digitalWrite(player4LedPin, HIGH);
        Serial.println("Player 4 pressed first!");
      }
    }
  }

  if (digitalRead(resetButtonPin) == HIGH) {
    player1Pressed = 0;
    player2Pressed = 0;
    player3Pressed = 0;
    player4Pressed = 0;

    digitalWrite(player1LedPin, LOW);
    digitalWrite(player2LedPin, LOW);
    digitalWrite(player3LedPin, LOW);
    digitalWrite(player4LedPin, LOW);
  }
}

该程序使用了6个数字输入引脚和4个数字输出引脚，实现了4人抢答器的功能。程序的基本思路是：等待用户按下开始按键，然后进入抢答状态。在抢答状态下，程序不断检测4个抢答按键是否被按下，如果有用户首先按下了抢答按键，则该用户成为本次抢答的胜者。当有用户胜出后，程序通过串口输出该选手的号码，并点亮该选手对应的LED灯。同时，程序记录哪个选手胜出，并防止后续的抢答按键产生作用。当用户按下复位按键时，程序将上一次抢答的状态清除，进入下一次等待状态。

注：该程序中使用了一个while循环，在循环结束前，程序会一直检测抢答按键是否被按下，因此可能存在一定的延迟。