《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：

// 18.1 add two numbers wihout using arithmetic operator.
#include <iostream>
using namespace std;

int add(int x, int y)
{
    int sum;
    int carry;
    int bx, by;
    int base;
    
    base = 1;
    carry = 0;
    sum = 0;
    while (base != 0) {
        bx = x & base;
        by = y & base;
        base <<= 1;
        sum |= ((bx) ^ (by) ^ carry);
        carry = ((bx & by) || (bx & carry) || (by & carry)) ? base : 0;
    }
    
    return sum;
}

int main()
{
    int x, y;
    
    while (cin >> x >> y) {
        cout << add(x, y) << endl;
    }
    
    return 0;
}