Question

编写一个c#窗体应用程序，对于输入的正整数n，计算1!+2!+3！+...+n！的值并输出

Answer 1

private int f(int i)
        {
            if (i == 1)
            {
                return 1;
            }
            else
            {
                return f(i - 1) + g(i);
            }
        }

        private int g(int i)
        {
            if (i == 1)
            {
                return 1;
            }
            else
            {
                return g(i - 1) * i;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int n = Convert.ToInt32(textBox1.Text);
            textBox2.Text = f(n).ToString();
        }

Answer 2

class Program {

}

{

} }

Answer 3

这么简单。