#include<stdio.h>
int main()
{
int num,count=0,i=0,ret=0;
scanf("%d",&num);
count=num;
while(num>1)
{
num/=2;
ret++;
}
printf("log2 of %d = %d\n",count,ret);
return 0;
}
/*
64
log2 of 64 = 6
Press any key to continue
*/
//注意：在两个数做运算时，只要有一个是浮点数，计算的结果均为浮点数！
原文：http://www.cnblogs.com/gcter/p/5729712.html