C++ Program to calculate sum of two numbers without using arithmetic operator [DEVCPP/GCC]

EXPLANATION

Let the two numbers a and b be 3 and 2. These numbers are represented in binary as:

3 = 011

2 = 010

ITERATION 1

I. Calculate carry (carry = a & b)

a: 0 1 1

b: 0 1 0

_____
0 1 0

II. Calculate sum (a = a ^ b) (XOR operation)

a: 0 1 1

b: 0 1 0

_____
0 0 1

III. Update the value of b (b = carry << 1)

b = carry << 1
b = 0 1 0 << 1
b = 1 0 0

ITERATION 2

I. Calculate carry (carry = a & b)

a: 0 0 1
b: 1 0 0
_____
0 0 0

II. Calculate sum (a = a ^ b)

a: 0 0 1
b: 1 0 0
_____
1 0 1

III. Update the value of b (b = carry << 1)

b = carry << 1
b = 0 0 0 << 1
b = 0 0 0

Since, b has become 0, the calculation stops and leads us with sum as 1 0 1(5).

PROGRAM

// Program to calculate sum of two numbers without using arithmetic operator

#include <iostream>

using namespace std;

int main()
{
int a,b,carry;

cout<<"ENTER A: ";
cin>>a;

cout<<"ENTER B: ";
cin>>b;

while (b != 0)
{
carry = (a & b) ;
a = a^b;
b = carry << 1;
}

cout<<"SUM : "<<a;

return 0;
}

OUTPUT