《Cracking the Coding Interview》——第18章：难题——题目1

2014-04-29 00:56

题目：不用算数运算，完成加法。

解法：那就位运算吧，用加法器的做法就可以了。

代码：

 1 // 18.1 add two numbers wihout using arithmetic operator.

 2 #include <iostream>

 3 using namespace std;

 4 

 5 int add(int x, int y)

 6 {

 7     int sum;

 8     int carry;

 9     int bx, by;

10     int base;

11     

12     base = 1;

13     carry = 0;

14     sum = 0;

15     while (base != 0) {

16         bx = x & base;

17         by = y & base;

18         base <<= 1;

19         sum |= ((bx) ^ (by) ^ carry);

20         carry = ((bx & by) || (bx & carry) || (by & carry)) ? base : 0;

21     }

22     

23     return sum;

24 }

25 

26 int main()

27 {

28     int x, y;

29     

30     while (cin >> x >> y) {

31         cout << add(x, y) << endl;

32     }

33     

34     return 0;

35 }