What is the best way to add two numbers without using the + operator?

Question

A friend and I are going back and forth with brain-teasers and I have no idea how to solve this one. My assumption is that it\'s possible with some bitwise operators, but n

Answer 1

Java solution with bitwise operators:

// Recursive solution
public static int addR(int x, int y) {

    if (y == 0) return x;
    int sum = x ^ y; //SUM of two integer is X XOR Y
    int carry = (x & y) << 1;  //CARRY of two integer is X AND Y
    return addR(sum, carry);
}

//Iterative solution
public static int addI(int x, int y) {

    while (y != 0) {
        int carry = (x & y); //CARRY is AND of two bits
        x = x ^ y; //SUM of two bits is X XOR Y
        y = carry << 1; //shifts carry to 1 bit to calculate sum
    }
    return x;
}

Answer 2

Why not just incremet the first number as often, as the second number?

Answer 3

Adding two integers is not that difficult; there are many examples of binary addition online.

A more challenging problem is floating point numbers! There's an example at http://pages.cs.wisc.edu/~smoler/x86text/lect.notes/arith.flpt.html

Answer 4

Python codes: (1)

add = lambda a,b : -(-a)-(-b)

use lambda function with '-' operator

(2)

add= lambda a,b : len(list(map(lambda x:x,(i for i in range(-a,b)))))