找出出现奇数次的元素

#include<iostream>
using namespace std;

bool question1(const int a[],const int n, int &num)
{
    int temp = 0;
    for(int i = 0;i< n;i++)
       temp ^= a[i];
    num = temp;
    return true;
}

bool question2(const int a[],const int n, int &num1,int &num2)
{
    unsigned int temp = 0;
    for(int i = 0;i< n;i++)
       temp ^= a[i];
    int k = 0;
    while(temp&1 == 0)
    {
      temp = temp>>1;
      k++;
    }
    num1 = 0;
    num2 = 0;
    for(int i = 0;i< n;i++)
    {
     if(((a[i]>>k)&1) == 0) ///注意这里的执行顺序
      num1 ^= a[i];
     else
      num2 ^= a[i];
    }
    return true;
}

int main()
{
    int a1[] = {1,1,2,2,3,3,4};
    int a2[] = {1,1,2,3,4,4};
    int r1,r2,r3;
    question1(a1,7,r1);
    question2(a2,6,r2,r3);
    cout<<r1<<" "<<r2<<" "<<r3;

}