控制台输出时小数位数定义

using System;
namespace program
{
    class program1
    {
        static void Main(string[] args)
        {
            int a = 4, b = 5, c = 6;
            int p = (a + b + c) / 2;
            double s = Math.Sqrt(p * (p - a) * (p - b) * (p - c));
            Console.WriteLine("三角形的面积是{0:f2}", s);//保留两位小数
        }
    }
}