c#使用double时的大数字表示

Question

我有这个程序,从双变量中获取所有数字,删除小数点和减号,并分别添加每个数字.这是:

static void Main(string[] args)
    {

            double input = double.Parse(Console.ReadLine());

                char[] chrArr = input.ToString().ToCharArray();

                input = 0;

                foreach (var ch in chrArr)
                {
                    string somestring = Convert.ToString(ch);
                    int someint = 0;
                    bool z = int.TryParse(somestring, out someint);
                    if (z == true)
                    {
                        input += (ch - '0');
                    }
                }

The problem is for example when I enter "9999999999999999999999999999999...." and so on, it gets represented as 1.0E+254 and what so my program just adds 1+0+2+5+4 and finishes. Is there efficient way to make this work properly ? I tried using string instad of double, but it works too slow..

Answer 1

你不能存储"9999999999999999999999999999999..."为双double精度- 只有15或16位精度.编译器为您提供了它可以代表您所要求的最接近的双倍,即1E254.

我会研究为什么使用string缓慢或使用BigInteger