源代码：
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace 实例_032_递归算法的经典面试题
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int num;
            num = Convert.ToInt32(textBox1.Text);
            if(int.TryParse(textBox1.Text,out num ))
            {
                label2.Text="计算的结果是:"+Get(num);
            }
            else
            {
                MessageBox.Show("输入错误，请输入正确的数值!","警告!");
            }
        }
         
         int Get(int num)
        {
            if (num <= 0)
                return 0;
            else
                if (num >= 0 && num <= 2)
                return 1;
            else
                return Get(num-1)+Get(num-2);
        }

         private void Form1_Load(object sender, EventArgs e)
         {

         }
刚从C转过来 看到这段程序里面的int Get(int num)程序段实在是有点不明白 看着像C里面的子函数但是这里就不知道该叫什么或是该怎么用？或是有什么具体的格式吗？