We are required to write a JavaScript function add() that takes in two numbers m and n. The function should, without using the four basic arithmetic operations add the two numbers taken as input and return the sum.
Example
The code for this will be −
const m = 67, n = 33;
const add = (x, y) => {
while(y !== 0){
let carry = x & y;
x = x ^ y;
y = carry << 1;
};
return x;
};
console.log(add(m, n));Explanation
Sum of two bits can be obtained by performing XOR (^) of the two bits. And the carry bit can be obtained by performing AND (&) of two bits.
We have here used an extended version of the Half Adder logic that can be used to add 2 single bits to add two integers. If x and y don’t have set bits at the same position(s), then bitwise XOR (^) of x and y gives the sum of x and y.
To incorporate common set bits also, bitwise AND (&) is used. Bitwise AND of x and y gives all carry bits. We have calculated (x & y) << 1 and added it to x ^ y to get the required result.
Output
And the output in the console will be −
100