int anode[4]={6,8,9,12};
int cath[7]={11,7,4,2,13,10,5};
unsigned short time=0;

void setup(){
    for(short i=2;i<=13;i++)
        pinMode(i,OUTPUT);
}

short count(short n){
    short count=0;
    while(n!=0){
        n/=10;
        count+=1;  
    }
    return count;
}
void reset(){
    for(short i=0;i<=6;i++){
        digitalWrite(*(cath+i),HIGH);
    }
}
void display(int n) {
  reset();
  if(n==1||n==7){
    digitalWrite(7,LOW);
    digitalWrite(4,LOW);
    if(n==7){digitalWrite(11,LOW);}
  }
  for(short i=0;i<=6;i++){
    if(n==1||n==7){break;}
    if(n==0&& *(cath+i)==5){continue;}
    if(n==2&&(*(cath+i)==4||*(cath+i)==10)){continue;}
    if(n==3&&(*(cath+i)==13||*(cath+i)==10)){continue;}
    if(n==4&&(*(cath+i)==11||*(cath+i)==2||*(cath+i)==13)){continue;}
    if(n==5&&(*(cath+i)==13||*(cath+i)==7)){continue;}
    if(n==6 && *(cath+i)==7){continue;}
    if(n==9 && *(cath+i)==13){continue;}
    digitalWrite(*(cath+i),LOW);
    }
}

void loop(){
  short val=9999;
  while(val!=0){
      short dup=val;
      short sum=count(dup);
      for(short i=0;i<=sum;i++){
      short temp=dup%10;
      dup/=10;
      display(temp);
      digitalWrite(anode[i],HIGH);
      delay(25);
      digitalWrite(anode[i],LOW);
   }
   if((millis()-time)>=1000){
    val--;
    time=millis();
   }
 }
}