371 .  Sum of Two Integers   Given two integers  a  and  b , return  the sum of the two integers without using the operators   +   and   - .   Example 1: Input:  a = 1, b = 2 Output:  3 Example 2: Input:  a = 2, b = 3 Output:  5   Constraints: -1000 <= a, b <= 1000 Solution :  C++ : class Solution { public:     int getSum(int a, int b) {         if (b==0) return a;         int sum = a ^ b;         int cr = (unsigned int) (a & b) << 1;         return getSum(sum, cr);                       } }; Java :  class Solution {     public int getSum(int a, int b) {                 while(b != 0){         int tmp = (a & b) << 1;         a = a ^ b;         b = tmp;     }     return a;     } } Explaination :