void setup() {
  Serial.begin(115200);
  Serial.println("Hello, STM32!");
  for(int i=2;i<=8;i++)
  {
    pinMode(i, OUTPUT);
  }
}

void loop() {
    for(int i=0;i<=9;i++){
        display(i);
        delay(5000);
    }
}
void display(int num){
     switch(num){
      case 0 : digitalWrite(2, LOW);
              digitalWrite(3, LOW);
              digitalWrite(4, LOW);
              digitalWrite(5, LOW);
              digitalWrite(6, LOW);
              digitalWrite(7, LOW);
              digitalWrite(8, HIGH);
              break;
      case 1 : digitalWrite(2, HIGH);
              digitalWrite(3, LOW);
              digitalWrite(4, LOW);
              digitalWrite(5, HIGH);
              digitalWrite(6, HIGH);
              digitalWrite(7, HIGH);
              digitalWrite(8, HIGH);
              break;
      case 2 : digitalWrite(2, LOW);
              digitalWrite(3, LOW);
              digitalWrite(4, HIGH);
              digitalWrite(5, LOW);
              digitalWrite(6, LOW);
              digitalWrite(7, HIGH);
              digitalWrite(8, LOW);
              break;        
      case 3 : digitalWrite(2, LOW);
              digitalWrite(3, LOW);
              digitalWrite(4, LOW);
              digitalWrite(5, LOW);
              digitalWrite(6, HIGH);
              digitalWrite(7, HIGH);
              digitalWrite(8, LOW);
              break;        
      case 4 : digitalWrite(2, HIGH);
              digitalWrite(3, LOW);
              digitalWrite(4, LOW);
              digitalWrite(5, HIGH);
              digitalWrite(6, HIGH);
              digitalWrite(7, LOW);
              digitalWrite(8, LOW);
              break;
      case 5 : digitalWrite(2, LOW);
              digitalWrite(3, HIGH);
              digitalWrite(4, LOW);
              digitalWrite(5, LOW);
              digitalWrite(6, HIGH);
              digitalWrite(7, LOW);
              digitalWrite(8, LOW);
              break;        
     }

}