โปรเจ็คเด็ก ป.2 อธิบาย

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

namespace ConsoleApplication2
{
    class Program
    {
        static void Enter() //เมทตอดเอ็นเทอร์
        {
            Console.Write("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n");
        }
        static void ST_END(int A)//เมทตอดโชว์ประโยคเริ่มโปรแกรม
        {
        Enter();  //ไปที่เมดตอด  Enter()
        if(A==1)
            {
                Console.Write("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n \t\t\tWelcome!!");
                Console.Write("\n\n\n\n\n\n\n\n\n\n\n\n\n");
            }
        else if (A == 2)
            {
                Console.Write("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n \t\t\tEnd Program");
                Console.Write("\n\n\n\n\n\n\n\n\n\n\n\n\n");
            }
        Console.ReadLine();
        Enter();  //ไปที่เมดตอด  Enter()
    }
        static double Operation(double A, double B, string BokLop)//เมทตอดบวก  ลบ  คูณ  หาร
        {
            double sum=0;
            if (BokLop == "Bok")
            {
                sum= A + B;
            }
            else if (BokLop == "Lop")
            {
                sum= A - B;
            }
            else if (BokLop == "Han") {
                sum = A / B;
            }
            else if (BokLop == "Kon")
            {
                sum = A * B;
            }
            return sum;
        }
        static void show(double[] ar, double dwPc)//เมทตอดแสดงค่า
        {
            Console.WriteLine("\n==========<|| SHOW ||>=========");
            Console.Write("\nThe real : {0} Bath", ar[0]);
            Console.Write("\nInterest to be paid : {0} ", ar[1]);
            Console.Write("\nBalance to be paid : {0} Bath", ar[2]);
            Console.Write("\nFinance / period ({0} year / {1} months): {2:f1} Bath", dwPc, Operation(dwPc ,12,"Kon"), ar[3]);
            Console.Write("\n+ vat 7% : {0} Bath", ar[4]);
            Console.WriteLine("\n============================");
        }
        static void Car() //เมทตอดรับค่า
        {
            Console.WriteLine("\n==========<|| Input ||>=========");
            double[] ar = new double[10];
            Console.Write("Price of car : ");
            double slCar = double.Parse(Console.ReadLine());
            Console.WriteLine("--------------------------------");
            Console.Write("down payment of car : ");
            double dwCar = double.Parse(Console.ReadLine());
            Console.WriteLine("--------------------------------");
            Console.WriteLine("Down 12 , 24 ,36 , 48 , 60  (month)");
            Console.Write("Installment of the how many (month): ");
            double dwPc = double.Parse(Console.ReadLine());
            Console.WriteLine("--------------------------------");
            Console.WriteLine("Down 0-10 %  (Persen)");
            Console.Write("how many percent interest (%):");
            double per = double.Parse(Console.ReadLine());

            if (dwPc == 12) dwPc = 1;
            else if (dwPc == 24) dwPc = 2;
            else if (dwPc == 36) dwPc = 3;
            else if (dwPc == 48) dwPc = 4;
            else if (dwPc == 60) dwPc = 5;

            ar[0] = Operation(slCar, dwCar, "Lop");    //=slCar- dwCar
            ar[1] = Operation(Operation(per, 100, "Han"), ar[0], "Kon");  //=(per, 100)*ar[0]
            ar[2] = Operation(ar[0], ar[1], "Bok");  //=ar[0]+ ar[1]
            ar[3] = Operation(ar[2], Operation(dwPc, 12, "Kon"), "Han");  //=ar[2]/(dwPc* 12)
            ar[4] = Operation(0.07, Operation(ar[3], ar[3], "Bok"), "Kon");  //=0.07/(ar[3]+ ar[3])

            ar[4] = Math.Round(ar[4], 1);  //ปัดเศษ
            show(ar, dwPc);  //แสดงค่าเมดตอดโชว์
       }
        static void Main()//เมทตอดหลัก
        {
            string YN = "n";//ประกาศ YN ตั่งค่าเริ่มต้นเป็น  n
            int sw=1;  //ประกาส  sw  ตั่งค่าเริ่มต้น
            ST_END(1);//ไปที่เมดตอด ST_END(1)  ใส่ค่า 1
                do{
                    if (YN == "N" || YN == "n" || YN == "no" || YN == "No" || YN == "NO" || YN == "nO")
                        {
                            Car();  //ไปที่เมดตอด  Car()
                            Console.Write("\nEnd now? (y/n) : ");
                            YN = Console.ReadLine(); //รับค่าเยสหรือโนว
                        }
                    if (YN == "Y" || YN == "y" || YN == "Yes" || YN == "yes" || YN == "Ye" || YN == "ye" || YN == "YES")
                        {
                            sw = 0;
                        }
                    else {
                            Console.Write("\nWong !!input Y(Yes)  or N(No)");
                            Console.Write("\nEnd now? (y/n) : ");
                            YN = Console.ReadLine();  //รับค่าเยสหรือโนว
                        }
                    Enter();  //ไปที่เมดตอด  Enter()
              } while (sw!=0); //ถ้า sw ไม่เท่ากับ 0 ก็จะไม่หลุด

            ST_END(2);  //ไปที่เมดตอด ST_END(2)  ใส่ค่า 2
          }
     }
 }