namespace HanShu
{
    class Class1
    {
        /// <summary>
        /// 这是一个加法运算的函数
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <returns></returns>
        public int JiaFa(int a, int b)
        {
            return a + b;
        }

        /// <summary>
        /// 无返回值，无参数
        /// </summary>
        public void DaYin()
        {
            Console.WriteLine("helloworld");
        }

        /// <summary>
        /// 累加求和
        /// </summary>
        /// <param name="n"></param>
        /// <returns></returns>
        public int Qiuhe(int n)
        {
            int sum = 0;
            for (int i = 1; i <= n; i++)
            {
                sum += i;
            }

            return sum;
        }

    }
}
namespace HanShu
{
    class Program
    {
        //函数：是一个带有输入参数、输出参数、返回值的代码块
       
        static void Main(string[] args)
        {
            int a, b;
            a = 3;
            b = 5;

            Class1 cc = new Class1();
            int c = cc.JiaFa(a,b);

            Console.WriteLine(c);

            cc.DaYin();

            Console.WriteLine(cc.Qiuhe(5));
            Console.ReadLine();
        }
    }
}

函数的输入，输出