what method does the computer use to add unsigned integers :     int main(){
        unsigned int num1; 
        unsigned int num2;
        unsigned int sum = num1 + num2;
        cout << hex << sum;
    }

If i have two unsigned integers say num1 and num2. 
And then I  tell the computer to unsigned int sum = num1 + num2;  
What method does the computer use to add them, would it be two's complement. Would the sum variable be printed in two's complement.