key lab com Bonus คิดด้วยนะ เวลา ลอกอะ

ข้อ 1
using System;
using System.Collections.Generic;
public class MyClass
{
 public static void Main()
 {

  Console.Write("A: ");
  int A = int.Parse(Console.ReadLine());
  Console.Write("B: ");
  int B = int.Parse(Console.ReadLine());
  int x = A*B;
  string S = x.ToString();
  string t = A.ToString();
  string u = B.ToString();
  string Y = S + A;
  string y = A + S;
  int a = int.Parse(Y);
  int b = int.Parse(y);
  int Sum = a-b;
  Console.WriteLine("{0} - {1} = {2}",a,b,Sum);
  Console.ReadLine();
 }
 
}


ข้อ 2

using System;
using System.Collections.Generic;
public class MyClass
{
 public static void Main()
 {
  Console.Write("Score: ");
  int Score = int.Parse(Console.ReadLine());
  Console.Write("Mean: ");
  int Mean = int.Parse(Console.ReadLine());
  if(Score>=Mean)
  {
  if((Score>Mean)&&(Score>=80))
         {
              Console.WriteLine("Grade A!");
        }
        else if (Score>Mean)
          {
               Console.WriteLine("Grade B!");
          }
        else
         {
              Console.WriteLine("Grade C!");
         }
  }
  else
  {
   if((Score<Mean)&&(Score<40))
          {
              Console.WriteLine("Grade F!");
         }
   else
          {
              Console.WriteLine("Grade D!");
          }
  }
 } 
}

ข้อ 3
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ข้อ 4
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ข้อ 5

using System;
using System.Collections.Generic;
public class MyClass
{
 static int Factorial(int n)
   {
  int sum = 1;
     while (n>0)
      {
      sum *= n;
      n= n-1;
      }
     return sum;
 }
 public static void Main()
 {
  Console.Write("A: ");
  int A = int.Parse(Console.ReadLine());
  long a = Factorial(A);
  Console.Write("B: ");
  int B = int.Parse(Console.ReadLine());
  long b = Factorial(B);
  Console.Write("C: ");
  int C = int.Parse(Console.ReadLine());
  long c = Factorial(C);
  long sum = a+b+c;
  if (((A>=0)&&(A<=20))&((B>=0)&&(B<=20))&((C>=0)&(C<=20)))
  {
  Console.WriteLine("{0}! + {1}! + {2}! = {3}",A,B,C,sum);
  }
  Console.ReadLine();
 }
}

ข้อ 3

using System;
class Program
{
    static void Main()
    {
         A = ;
        double B = 1 / 2;
         C = ;
         D = ;
        int E = 1;

        if (!(Math.Sin(A) != B || C == D || C))
            E--;

        Console.WriteLine(E);
    }
}

ข้อ อื่น รอไปก่อนนะ บางข้ออาจจะผิดพลาดบ้าง อย่าโวยวาย กำลังแก้ใขอยู๋