面试题47：不用加减乘除做加法

public class Add {

public int add(int num1, int num2)
{
int sum, carry;

do
{
sum = num1 ^ num2;
carry = (num1 & num2) << 1;

num1 = sum;
num2 = carry;
}while(num2 != 0);

return num1;
}

public static void main(String[] args) {
System.out.println(new Add().add(10, 7));
}

}