函数的调用
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace hanshu
{
    class Program
    {
       //传值:四种方式
        //1.没有返回值,没有输入值
        //2.有返回值,没有输入值
        //3.没有返回值,有输入值
        //4.有返回值,有输入值
        //传址
        
        
        //(static/public)  返回类型  函数名 (参数类型,参数名)
        
        
        //没有返回值,没有输入值
        /// <summary>
        /// 累加求和,没有输入值,没有返回值
        /// </summary>
        public void Leijia()
        {
            Console.Write("请输入一个正整数");
            int a = int.Parse(Console.ReadLine());
            int sum = 0;
            for (int i = 1; i <= a; i++)
            {
                sum += i;
            }
            Console.WriteLine(sum);
        }
        //有输入值,没有返回值
        /// <summary>
        /// 累加求和,有输入值,没有返回值
        /// </summary>
        /// <param name="a"></param>
        public void Leijia(int a)
        {
            
            int sum = 0;
            for (int i = 1; i <= a; i++)
            {
                sum += i;
            }
            Console.WriteLine(sum);
        }
        /// <summary>
        /// 累加求和,没有输入值,只有返回值(int)
        /// </summary>
        /// <returns></returns>
        public int Leijia1()
        {
            Console.Write("请输入一个正整数");
            int a = int.Parse(Console.ReadLine());
            int sum = 0;
            for (int i = 1; i <= a; i++)
            {
                sum += i;
            }
            return sum;
            
        }
        /// <summary>
        /// 累加求和,有输入值(int),有返回值(int)
        /// </summary>
        /// <param name="a"></param>
        /// <returns></returns>
        public int Leijia1(int a)
        {
            int sum = 0;
            for (int i = 1; i <= a; i++)
            {
                sum += i;
            }
            return sum;
        }
        static void Main(string[] args)
        {
            Program pp = new Program();
            //Console.Write("请输入一个正整数");
            //int a = int.Parse(Console.ReadLine());
            //pp.Leijia(a);
            //pp.Leijia();
            //pp.Leijia();
            //int sum = pp.Leijia1();
            //Console.WriteLine(sum);
            //int sum=pp.Leijia1(6);
            //Console.WriteLine(sum);
            lei hanshu=new lei();
            hanshu.Leijia();
            haha heng = new haha();
            heng.hehe();
Console.ReadLine();
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace hanshu
{
    class lei
    {
        public void Leijia()
        {
            Console.WriteLine("告诉我我成功了!!!!");
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace hanshu
{
    class haha
    {
        public void hehe()
        {
            Console.WriteLine("再告诉我我成功了!!!!");
        }
    }
}
原文:http://www.cnblogs.com/xiongxiaobai/p/5272101.html