4. 자바 성적처리(클래스)

import java.util.Scanner;
 
public class aa {
 
 private int num;
 private int num2;
 
 double sum;
 
 public void getValue()
 {
  System.out.println("첫번 째 수 : "+num);
  System.out.println("첫번 째 수 : "+num2);
 }
 public void setValue(int num, int num2)
 {
  this.num = num;
  this.num2 = num2;
 }
 public int plus()
 {
  sum = num+num2;
  return (int)sum;
 }
 public int minus()
 {
  sum = num-num2;
  return (int)sum;
 }
 public int x()
 {
  sum = num*num2;
  return (int)sum;
 }
 public double d()
 {
  sum =((double)num/(double)num2);
  return sum;
 }
 public static void main(String[] args)
 { 
  Scanner sc = new Scanner(System.in);
  int number1,number2;
  char select, loop;
  aa a = new aa();//number1,number2
  do {
   System.out.print("첫 번째 수 : ");
   number1 = sc.nextInt();
   System.out.print("연산(+,-,*,/) : ");
   select = sc.next().charAt(0);
   System.out.print("두 번째 수 : ");
   number2 = sc.nextInt();
   a.setValue(number1, number2);
    switch(select)
    {
           case '+':
               System.out.println(a.plus());
               break;
           case '-':
            System.out.println(a.minus());
               break;
           case '*':
            System.out.println(a.x());
               break;
           case '/':
            System.out.println(a.d());
               break;
               
               default:
                   System.out.println("잘못된 연산입니다.");        
          }
    System.out.println("계속 진행 합니까? Y or y");
    loop = sc.next().charAt(0);
  }while(loop == 'Y' || loop == 'y' );
  System.out.println("종료");
 }
}