//A NOTE: All comments are EX POST FACTO. This was the code from an actual lab I did in 2017.

#include "C:/users/USER/desktop/FUNCTIONS/FUNCTIONS.ino" //I had this library called FUNCTIONS.ino at some point.

void setup() {
  pinMode(2,INPUT); //All the inputs were assigned to DIP switches on a bread board.
  pinMode(3,INPUT);
  pinMode(4,INPUT);
  pinMode(5,INPUT);
  pinMode(A0,INPUT);
  pinMode(A1,INPUT);
  pinMode(A2,INPUT);
  pinMode(A3,INPUT);
  pinMode(8,OUTPUT); //All the outputs were sent to LEDs that were protected with 220 Ohm resistors at the ground.
  pinMode(9,OUTPUT);
  pinMode(10,OUTPUT);
  pinMode(11,OUTPUT);
  pinMode(12,OUTPUT);
}

void loop(){
  int a = digitalRead(2);
  int b = digitalRead(3);
  int c = digitalRead(4);
  int d = digitalRead(5);
  int e = digitalRead(A0);
  int f = digitalRead(A1);
  int g = digitalRead(A2);
  int h = digitalRead(A3);

  int carry_out,out1,out2,out3,out4; //All the various carry outs for the four bit adder.

  FOURADD(d,c,b,a,h,g,f,e,&carry_out,&out1,&out2,&out3,&out4);

  digitalWrite(8,carry_out); //Writing the outputs to LEDs.
  digitalWrite(9,out1);
  digitalWrite(10,out2);
  digitalWrite(11,out3);
  digitalWrite(12,out4);
}