[20.1] Add two number without + or any other arithmetic operators

1. Example

Add each digit, and carry the one as necessary
Sum ONLY:
759
674
___
323

9  = 1001
4  = 0100
----------
13 = 1101  = 9^4
====> XOR

 carry ONLY:
 7 5 9
 6 7 4
____
1110

9  = 1001
4  = 0100
----------
0 = 0000  = 9&4
====> AND


  2 = 0010
10 = 1010
-------------
12 = 1100
2^10 = 1000 =8
2&10= 0010 
0010 << 1 = 0100 =4

8^4 =  1000^0100 = 1100 = 12

2. Implementation

public int addTwoNumber_No_Arithm(int a, int b)
{
      if (b==0) return a; // no carry
      int sum = a^b;        // add without carrying
      int carry = (a&b)<<1; // carry, but no add
      return addTwoNumber_No_Arithm(sum, carry); 
}

3.Similar Ones