int a_in = 2;
int b_in = 3;
int c_in = 4;

int a_send = 7;
int b_send = 6;
int c_send = 5;

int sum_rec = 8;
int carry_rec = 9;

int sumled = 10;
int carryled = 11;

void setup() {
  Serial.begin(9600);
  pinMode(a_in, INPUT);
  pinMode(b_in, INPUT);
  pinMode(c_in, INPUT);

  pinMode (a_send, OUTPUT);
  pinMode(b_send, OUTPUT);
  pinMode(c_send, OUTPUT);

  pinMode(sum_rec, INPUT);
  pinMode(carry_rec, INPUT);

  pinMode(sumled, OUTPUT);
  pinMode(carryled, OUTPUT);
}

void loop() {
  
  int A = digitalRead(a_in);
  int B = digitalRead(b_in);
  int Cin = digitalRead(c_in);

  Serial.println(A);
  Serial.println(B);
  Serial.println(Cin);

  digitalWrite(a_send, A);
  digitalWrite(b_send, B);
  digitalWrite(c_send, Cin);
 
  delay(100);

  int sumOutput = digitalRead(sum_rec);
  int carryOutput = digitalRead(carry_rec);

  Serial.print("Sum: ");
  Serial.print(sumOutput);
  Serial.print(" Carry: ");
  Serial.println(carryOutput);

digitalWrite(sumled, sumOutput);
digitalWrite(carryled, carryOutput);
}