int led[]={6,7,8,9,10,11,12,13};
bool upDown=1;
int i=0;
int delayTime=200;
long lastTime=0;
int sw1=2;
int sw2=3;

void setup() 
{                
  for(int i=0; i<=7; i++)
  {
    pinMode(led[i], OUTPUT);
    digitalWrite(led[i],LOW);
  } 
  pinMode(sw1, INPUT_PULLUP);   
  pinMode(sw2, INPUT_PULLUP);  
  Serial.begin(115200);
  i=0;
}

void loop() 
{
  if((digitalRead(sw1)==0)&&(i<9))
  {
    i++;
    out8bit(i);
  }
  if((digitalRead(sw2)==0)&&(i>0))
  {
    i--;
    out8bit(i);
  }
  Serial.print("i=");
  Serial.println(i);
  delay(100);
}

const char segment[]={  B00111111,
                        B00000110,
                        B01011011,
                        B01001111,
                        B01100110,
                        B01101101,
                        B01111101,
                        B00000111,
                        B01111111,
                        B01101111,
                        B00000000 };

void out8bit(unsigned char data)
{
  digitalWrite(led[0],segment[data] & B00000001);
  digitalWrite(led[1],segment[data] & B00000010);
  digitalWrite(led[2],segment[data] & B00000100);
  digitalWrite(led[3],segment[data] & B00001000);
  digitalWrite(led[4],segment[data] & B00010000);
  digitalWrite(led[5],segment[data] & B00100000);
  digitalWrite(led[6],segment[data] & B01000000);
  digitalWrite(led[7],segment[data] & B10000000);
}