循环求和多项式累加求和

Question

Answer 1

static void Main(string[] args) 
{ 
    double s = 0;
    for (int i = 1;i<=100;i++)
    {
        if(i<=10)
        {
            s += i;
            s += i*i;
            s += 1.0/i;
        }else if (i <=50)
        {
            s+=i;
            s+=i*i;
        }else
            s+=i;
    }
    Console.WriteLine(s.ToString("f3")); //保留3位小数
}