Math 类的方法概要

用sivlerlight做动画和特效时经常会用到Math类，总结一下。
参考：http://www.cnblogs.com/del/archive/2011/01/03/1924746.html

//返回数字的绝对值
Console.WriteLine(Math.Abs(-10));
//向上进位取整
Console.WriteLine(Math.Ceiling(32.1));//33
Console.WriteLine(Math.Ceiling(32.0));//32
Console.WriteLine(Math.Ceiling(-32.1));//32
Console.WriteLine(Math.Ceiling((decimal)(7 + 9) / 10));
//向下舍位取整
Console.WriteLine(Math.Floor(32.9));//32
Console.WriteLine(Math.Floor(32.0));//32

Console.WriteLine(Math.Floor(-32.5));       //-33

Console.WriteLine(Math.Max(1, 9));//9
Console.WriteLine(Math.Min(1, 9));//1
Console.WriteLine(Math.Pow(2, 3));//8
//取指定位数的小数 四舍六入五考虑，五后非零就进一，五后皆零看奇偶，五前为偶应舍 去，五前为奇要进一

Math.Round(0.5);  // 0
Math.Round(1.5);  // 2
Math.Round(2.5);  // 2
Math.Round(3.5);  // 4
Math.Round(-0.5); // 0
Math.Round(-1.5); //-2
Math.Round(-2.5); //-2
Math.Round(-3.5); //-4

Math.Round(0.5, MidpointRounding.AwayFromZero);  // 1
Math.Round(1.5, MidpointRounding.AwayFromZero);  // 2 
Math.Round(2.5, MidpointRounding.AwayFromZero);  // 3
Math.Round(3.5, MidpointRounding.AwayFromZero);  // 4 
Math.Round(-0.5, MidpointRounding.AwayFromZero); //-1
Math.Round(-1.5, MidpointRounding.AwayFromZero); //-2
Math.Round(-2.5, MidpointRounding.AwayFromZero); //-3
Math.Round(-3.5, MidpointRounding.AwayFromZero); //-4


Console.WriteLine(Math.Round(3.4452, 2));//3.45 
Console.WriteLine(Math.Round(3.4552, 2));//3.46;
Console.WriteLine(Math.Round(3.4652, 2));//3.47;

Console.WriteLine(System.Double.NaN);//非数字
Console.WriteLine(System.Double.NegativeInfinity);//负无穷大
Console.WriteLine(System.Double.PositiveInfinity);//正无穷大