"Sword Finger Offer" Question 65: Addition without addition, subtraction, multiplication and division

// Interview question 65: Addition without addition, subtraction, multiplication, and division
 // Topic: Write a function to find the sum of two integers. It is required that +,-, ×, ÷ // four arithmetic symbols 
should not be used in the function body
 . 
#include <cstdio> int Add ( int num1, int num2) 
{ int sum = 0 ; // and int carry = 0 ; // carry do 
    { 
        sum = (num1 ^ num2); // bit XOR sum, none Carry 
        carry = (num1 & num2) << 1 ; // The position where the carry is generated is shifted to the left by 1         
        num1 = sum; 
        num2 = carry;


    
    

    


    } while (num2! = 0 ); // The problem is converted to the sum problem of sum and carry carry, and 

    return num1; 
}

// ====================测试代码====================
void Test(int num1, int num2, int expected)
{
    int result = Add(num1, num2);
    if (result == expected)
        printf("%d + %d is %d. Passed\n", num1, num2, result);
    else
        printf("%d + %d is %d. FAILED\n", num1, num2, result);
}

int main(int argc, char* argv[])
{
    Test(1, 2, 3);
    Test(111, 899, 1010);

    Test(-1, 2, 1);
    Test(1, -2, -1);

    Test(3, 0, 3);
    Test(0, -4, -4);

    Test(-2, -8, -10);

    return 0;
}

Test code

Analysis: The analysis process is important.

class Solution {
public:
    int Add(int num1, int num2)
    {
        int sum = 0;
        int carry = 0;
        
        do
        {
            sum = (num1 ^ num2);
            carry = (num1 & num2) << 1;
            
            num1 = sum;
            num2 = carry;
        } while (num2 != 0);
        
        return num1; 
    }
};

Niuke submission code