java诡异问题求解

Question

[code="java"]
package hello;

public class Test {
public static double area(double d)
{
return d * d;
}
public static double perimeter(double d)
{
return d * 4;
}
public static void main(String args[])
{
double d = 3.1;
System.out.println("面积：" + area(d));
System.out.println("周长：" + perimeter(d));
}
}
[/code]
输出面积竟然是9.610000000000001，怎么回事啊？

Answer 1

[url]http://www.blogjava.net/yeyiliang/archive/2006/09/13/69439.html[/url]
看看这个