Question

Can anybody explain how this function works?

public int TestAdd(int a,int b) {

        if(a <1)return b;       
        return(TestAdd((a&b)<<1,a^b));      
    }

Answer 1

Adding two matching set binary digits is equivalent to setting the next bit up: 1+1=2, and so on. So the function does that for all matching bits, then carries the unmatched ones over to another round. When no unmatched ones remain, it’s done.