//定义所有用到的引脚
int pin_a = 4;
int pin_b = 5;
int pin_c = 19;
int pin_d = 21;
int pin_e = 22;
int pin_f = 2;
int pin_g = 15;
int pin_dp = 18;

//定义存放所有输出引脚的数组
int pin_array[8] = {pin_a, pin_b, pin_c, pin_d, pin_e, pin_f, pin_g, pin_dp};

//定义数字显示逻辑的二维数组
int number_array[][8] = {
//a,b,c,d,e,f,g,dp
  {0,0,0,0,0,0,1,1},//0
  {1,0,0,1,1,1,1,1},//1
  {0,0,1,0,0,1,0,1},//2
  {0,0,0,0,1,1,0,1},//3
  {1,0,0,1,1,0,0,1},//4
  {0,1,0,0,1,0,0,1},//5
  {0,1,0,0,0,0,0,1},//6
  {0,0,0,1,1,1,1,1},//7
  {0,0,0,0,0,0,0,1},//8
  {0,0,0,0,1,0,0,1},//9
};

void setup() {
  //设置所有引脚为输出引脚,初始化所有引脚为高电平
  for (int i=0;i<8;i++){
    pinMode(pin_array[i], OUTPUT);
    digitalWrite(pin_array[i], HIGH);
  }

}

void loop() {
  //显示数字
  int num = 3;
  for (int i=0;i<8;i++){
    digitalWrite(pin_array[i],number_array[num][i]);
  }
}