Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example:
Given a = 1 and b = 2, return 3.

Credits:
Special thanks to @fujiaozhu for adding this problem and creating all test cases.
第一次在leetcode上看到反对票比赞成票多这么多的题目。
C实现代码如下：

int getSum(int a, int b) 
{
    int sum = a;
        
    while (b != 0)
    {
        sum = a ^ b;//calculate sum of a and b without thinking the carry 
        b = (a & b) << 1;//calculate the carry
        a = sum;//add sum(without carry) and carry
    }

    return sum;
}