Open In App
Related Articles

C++ program to implement full subtractor

Improve Article
Save Article
Like Article

Prerequisite : Full Subtractor
Given three inputs of Full Subtractor A, B, Bin. The task is to implement the Full Subtractor circuit and Print output states difference (D) and Bout of three inputs.

Introduction :
The full subtractor is used to subtract three 1-bit numbers  which are minuend, subtrahend, and borrow, respectively. The full subtractor has three input states and two output states. The two outputs are difference and borrow.

Here we have three inputs A, B, Bin and two outputs D, Bout. And the truth table for full subtractor is 

Logical Expression : 

Difference = (A XOR B) XOR Bin
Borrow Out = Ā Bin + Ā B + B Bin

Examples –

     Input         :    0 0 1
     Output      :     Difference=1, B-Out=1
     Explanation :   According to logical expression Difference= (A XOR B) XOR Bin  i.e (0 XOR 0) XOR 1  =1 ,
      B-Out=Ā Bin + Ā B + B Bin  i.e.  1AND 1 + 1 AND 0 + 0 AND 1 = 1.

    Input         :    1 0 1
    Output      :     Difference=0, B-Out=0

Approach :

  • We will take three inputs A, B, Bin.
  • By applying (A XOR B) XOR Bin gives the Value of Difference.
  • By applying Ā Bin + Ā B + B Bin gives the value of B-Out.


//c++ code for above approach
#include <bits/stdc++.h>
using namespace std;
//function to print difference and borrow out
void Full_Subtractor(int A,int B,int Bin){
   // Calculating value of Difference
    int Difference = (A ^ B) ^ Bin;
    //calculating NOT  value of a
    int A1 = not(A);
    //Calculating value of B-Out
    int B_Out = A1 & Bin | A1 & B | B & Bin;
    //printing the values
    cout<<"Difference = "<<Difference<<endl;
    cout<<"B-Out = "<<B_Out<<endl;
//Driver code
int main() {
    int A = 1;
    int B = 0;
    int Bin = 1;
    // calling the function
    Full_Subtractor(A, B, Bin);
    return 0;


Difference = 0
B-Out = 0
Whether you're preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, GeeksforGeeks Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we've already empowered, and we're here to do the same for you. Don't miss out - check it out now!

Last Updated : 17 Aug, 2021
Like Article
Save Article
Similar Reads