byte digits[] = {0x7e, 0x30, 0x6d, 0x79, 0x33, 0x5b, 0x5f, 0x70, 0x7f, 0x7b, 0x77, 0x1f, 0x4e, 0x3d, 0x4f, 0x47};
int inputPin[] = {2, 3, 4, 5};
int dataPin = 6;
int clockPin = 7;
int latchPin = 8;
int sum = 0;

void setup() {
  //Put your setup code here, to run once:

 for(int i = 0; i < 4; i++){
    pinMode(inputPin[i], INPUT);
  }
 pinMode(dataPin, OUTPUT);
 pinMode(clockPin, OUTPUT);
 pinMode(latchPin, OUTPUT);
}


void loop() {
  //Put your main code here, to run repeatedly:
   int bit0 = digitalRead(inputPin[0]) * 1;
   int bit1 = digitalRead(inputPin[1]) * 2;
   int bit2 = digitalRead(inputPin[2]) * 4;
   int bit3 = digitalRead(inputPin[3]) * 8;

      sum = bit0 + bit1 + bit2 + bit3;

   digitalWrite(latchPin, LOW);
 
   shiftOut(dataPin, clockPin, MSBFIRST, digits[sum]);

   digitalWrite(latchPin, HIGH);

delay(10);
}