日期:2014-05-20  浏览次数:20663 次

如何用位操作求余
题目如下:
int a;
a%32

如何用位操作来优化这个求余呢?

谢谢

------解决方案--------------------
[code=Java]public class mod{
public static void main(final String[] args)
{
System.out.println(modBy32(33));
System.out.println(modBy32(6));
System.out.println(modBy32(63));
System.out.println(modBy32(-33));
System.out.println(-33 % 32);
}

static int modBy32(int in){
int ret;
if(in > 0){
if(in < 32) return in;
while((ret = in - (in >> 5)*32) > 32);
return ret;
}
int input = -in;
while((ret = input - (input >> 5)*32) > 32);
return -ret;
}
}
[/java]

------解决方案--------------------
Java code


public class Test01 {

    public static void main(String args[]) {
        
        int a = 34;

        System.out.println(a % 32);

        System.out.println(a - (a >> 5 << 5)); 
    }
}