不使用sizeof，确定机器int大小

<pre name="code" class="cpp">#include<stdio.h>
int main()
{
<span style="white-space:pre">	</span>int i;
<span style="white-space:pre">	</span>unsignd int x = (unsigned int)~0;
<span style="white-space:pre">	</span>for (i = 1; x >>= 8; i++);
<span style="white-space:pre">	</span>printf("%d\n", i); 
}<pre name="code" class="cpp">#include<stdio.h>