面试题-32个开关判断是否打开

题目：有32个开关，有打开和关闭两种情况，写程序完成开关是否打开状态？简述实现思路即可。完成后评估自己的程序的运行效率，是否最快。

一般如下程序还是很容易想到，下面说明一下如何优化程序的运行速度。

#define GET_BIT(value, bit) ((value)&(1<<(bit)))>>bit        //读取指定位

void loopFunc2(int val)
{
    int tmp = 0;
    for (int i = 0; i < MAX_NUM; ++i)
    {
        tmp = GET_BIT(val, i);
        if (1 == tmp)
        {
            g_result[i] = 1;
        }
    }
}

当时想着空间换时间，定义数组来判断加速，但是实际效果未知，显然没有union+结构体位域 代码实现清晰明了。

typedef struct
{
  unsigned int bit0:1;
  unsigned int bit1:1;
  unsigned int bit2:1;
  unsigned int bit3:1;
  unsigned int bit4:1;
  unsigned int bit5:1;
  unsigned int bit6:1;
  unsigned int bit7:1;
  unsigned int bit8:1;
  unsigned int bit9:1;
  unsigned int bit10:1;
  unsigned int bit11:1;
  unsigned int bit12:1;
  unsigned int bit13:1;
  unsigned int bit14:1;
  unsigned int bit15:1;
  unsigned int bit16:1;
  unsigned int bit17:1;
  unsigned int bit18:1;
  unsigned int bit19:1;
  unsigned int bit20:1;
  unsigned int bit21:1;
  unsigned int bit22:1;
  unsigned int bit23:1;
  unsigned int bit24:1;
  unsigned int bit25:1;
  unsigned int bit26:1;
  unsigned int bit27:1;
  unsigned int bit28:1;
  unsigned int bit29:1;
  unsigned int bit30:1;
  unsigned int bit31:1;
}bitValue;

typedef union
{
  unsigned int bytedata;
  bitValue  bitdata;
} regValue;
regValue data;

data.bytedata= NUM;