(1)打印乘法口诀表
四方形
using System;
namespace huangjin
{
    class Test
    {
        static void Main(string[] args)
        {
            for (int i = 1; i <=9; i++)
            {
                for (int j = 1; j <=9; j++)
                {
                    Console.Write("{0}*{1}={2}\t",i,j,i*j);
                }
                Console.WriteLine();
            }
            Console.ReadKey();
        }      
    }
}
三角形
using System;
namespace huangjin
{
    class Test
    {
        static void Main(string[] args)
        {
            for (int i = 1; i <=9; i++)
            {
                for (int j = 1; j <=i; j++)
                {
                    Console.Write("{0}*{1}={2}\t",i,j,i*j);
                }
                Console.WriteLine();
            }
            Console.ReadKey();
        }      
    }
}
  

收到的鲜花

• 野比 于 2010-10-06 20:53 送鲜花  3朵   附言：我很赞同

实现简单四则运算小程序
面向过程式的
using System;
using System.Collections.Generic;
using System.Text;
namespace huangjin
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("请输入数字A：");
            string A = Console.ReadLine();
            Console.Write("请选择运算符号（+，-，*，/）：");
            string B = Console.ReadLine();
            Console.Write("请输入数字B：");
            string C=Console.ReadLine();
            string D="";
            if(B=="+")
                D=Convert.ToString(Convert.ToDouble(A)+Convert.ToDouble(C));
            if(B=="-")
                D=Convert.ToString(Convert.ToDouble(A)-Convert.ToDouble(C));
            if(B=="*")
                D=Convert.ToString(Convert.ToDouble(A)*Convert.ToDouble(C));
            if(B=="/")
                D=Convert.ToString(Convert.ToDouble(A)/Convert.ToDouble(C));
            Console.WriteLine("结果是："+D);
            Console.ReadKey();
        }
    }
}
面向对象的编程，不能提示除数为零的情况
using System;
using System.Collections.Generic;
using System.Text;

namespace DaHua1
{
   public class Operation
    {
       public static double GetResult(double numberA, double numberB, string operate)
       {
           double Result = 0d;
           switch (operate)
           {
               case"+":
                   Result = numberA + numberB;
                   break;
               case "-":
                   Result = numberA - numberB;
                   break;
               case "*":
                   Result = numberA * numberB;
                   break;
               case "/":
                   Result = numberA / numberB;
                   break;
           }
           return Result;
       }
    }
}

using System;
using System.Collections.Generic;
using System.Text;

namespace DaHua1
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                Console.Write("请输入数字A：");
                string strNumberA = Console.ReadLine();
                Console.Write("请选择运算符号（+，-，*，/）：");
                string strOperate = Console.ReadLine();
                Console.Write("请输入数字B：");
                string strNumberB = Console.ReadLine();
                string strResult = "";
                strResult = Convert.ToString(Operation.GetResult(Convert.ToDouble(strNumberA),
                    Convert.ToDouble(strNumberB), strOperate));
                Console.WriteLine("结果是："+strResult);
            }
            catch (Exception ex)
            {
                Console.WriteLine("您的输入有错：" + ex.Message);
            }
            Console.ReadKey();
        }
    }
}
面对象的编程，能提示除数为零并且要求重新输入

using System;
using System.Collections.Generic;
using System.Text;

namespace DaHua1
{
   public class Operation
    {
       public static double GetResult(double numberA, double numberB, string operate)
       {
           double Result = 0d;
           switch (operate)
           {
               case "+":
                   Result = numberA + numberB;
                   break;
               case "-":
                   Result = numberA - numberB;
                   break;
               case "*":
                   Result = numberA * numberB;
                   break;
               case "/":
                     Result = numberA / numberB;
                   break;
           }
           return Result;
       }
    }
}
using System;
using System.Collections.Generic;
using System.Text;

namespace DaHua1
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                Console.Write("请输入数字A：");
                string strNumberA = Console.ReadLine();
                Console.Write("请选择运算符号（+，-，*，/）：");
                string strOperate = Console.ReadLine();
                while (true)
                {
                    Console.Write("请输入数字B：");
                    string strNumberB = Console.ReadLine();
                    string strResult = "";
                    if (strOperate != "/")
                    {
                        strResult = Convert.ToString(Operation.GetResult(Convert.ToDouble(strNumberA),
                        Convert.ToDouble(strNumberB), strOperate));
                        Console.WriteLine("结果是：{0}" + strResult);
                        break;
                    }
                    else if (strNumberB != "0")
                    {
                        strResult = Convert.ToString(Operation.GetResult(Convert.ToDouble(strNumberA),
                        Convert.ToDouble(strNumberB), strOperate));
                        Console.WriteLine("结果是：" + strResult);
                        break;
                    }
                    else
                    {
                        Console.WriteLine("请检查除数的非零性，并再次输入");
                    }
                }
            }
            
            catch (Exception ex)
            {
                Console.WriteLine("您的输入有错：" + ex.Message);
            }
            Console.ReadKey();
        }
    }
}