Addition without addition, subtraction, multiplication and division

Bit operation is used here ,a+b The result of no carry and a^b equal ,0 + 1 = 1 == 0 ^ 1 = 1
a+b The carry of is equal to (a&b) << 1 3+1 The carry of is (11 & 1) << 1 = 10

public int add(int a, int b) {
    
        // Carry is 0 Jump out when 
        while(b != 0){
    
            // carry 
            int c = (a & b) << 1;
            // No carry and 
            a = a^b;
            // carry 
            b = c;
        }
        return a;
    }

operation 3+1：

1. 1 != 0 Into the loop carry c = (11 & 1) << 1 = 10
   a = 11 ^ 1 = 10
   b = 10

2. The second cycle 10 != 0
   c = (10 & 10) << 1 = 100
   a = 10 ^ 10 = 0
   b = 100

3. The third cycle 100 ! = 0
   c = ( 0 & 100) << 1 = 0
   a = a ^ 100 = 100
   b = 0;

4. end The result is 4