[TIL]パッケージ例、インスタンスメソッド

1）パッケージ追加内容

1-1)カプセルを割る行為

1-2）アクセス制御インジケータ

1～3）例

package part3.ex1.capsule2;

import java.io.IOException;
import java.util.Scanner;

public class Program1 {

   public static void main(String[] args) throws IOException {

      while (true) {

         int menu = inputMenu();

         Exam exam = new Exam();

         switch (menu) {
         case 1:
            Exam.input(exam);
            break;
         case 2:
        	 Exam.print(exam);
            break;
         case 3:
        	 Exam.load(exam);
            break;
         case 4:
        	 Exam.save(exam);
            break;
         case 5:
            exitProgram();
            break;
         }
      }

   }

   // Program의 Bottom 구성
   private static boolean exitProgram() {
      return true;
   }


   private static int inputMenu() {
      
      Scanner scan = new Scanner(System.in);

      int menu = 0;

      System.out.println("┌────────────────────────────────┐");
      System.out.println("│      성적관리 Main Menu          │");
      System.out.println("└────────────────────────────────┘");
      System.out.println("1. 입력");
      System.out.println("2. 출력");
      System.out.println("3. 읽기");
      System.out.println("4. 저장");
      System.out.println("5. 종료");
      System.out.print(">");
      menu = scan.nextInt();

      return menu;
   }

}

package part3.ex1.capsule2;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.Scanner;

public class Exam {

		private int kor;
		private int eng;
		private int math;
		
		   public static void save(Exam exam) throws IOException {      

			      File file = new File("res/data.txt");
			      FileOutputStream fos = new FileOutputStream(file);
			      PrintStream ps = new PrintStream(fos);

			      ps.printf("%d,%d,%d\n", exam.kor, exam.eng, exam.math);

			      ps.close();
			      fos.close();
			   }
		   
		   public static Exam load(Exam exam) throws IOException {
			      
			      File file = new File("res/data.txt");      
			      FileInputStream fis = new FileInputStream(file);
			      Scanner scan = new Scanner(fis);

			      String[] tmps = scan.nextLine().split(",");

			      scan.close();
			      fis.close();

			      exam.kor = Integer.parseInt(tmps[0]);
			      exam.eng = Integer.parseInt(tmps[1]);
			      exam.math = Integer.parseInt(tmps[2]);

			      return exam;
			   }
		   
		   public static void print(Exam exam) {
			      
			      Scanner scan = new Scanner(System.in);
			      
			      if (exam == null) {
			         System.out.println("성적이 입력되지 않았습니다. (Exam 객체가 존재하지 않음)");
			         return;
			      }

			      System.out.println("┌───────────────────────────────────┐");
			      System.out.println("│              성적 출력              │");
			      System.out.println("└───────────────────────────────────┘");
			      System.out.println("국어 : " + exam.kor);
			      System.out.println("영어 : " + exam.eng);
			      System.out.println("수학 : " + exam.math);

			      int total = exam.kor + exam.eng + exam.math;
			      System.out.println("총점 :" + total);
			      System.out.printf("평균 : %.2f\n", (total / 3.0));
			   }
		   
		   public static void input(Exam exam) {
			      
			      Scanner scan = new Scanner(System.in);
			      
			      System.out.println("┌───────────────────────────────────┐");
			      System.out.println("│              성적 출력              │");
			      System.out.println("└───────────────────────────────────┘");
			      
			      System.out.println("국어 >");
			      exam.kor = scan.nextInt();
			      System.out.println("영어 >");
			      exam.eng = scan.nextInt();
			      System.out.println("수학 >");
			      exam.math = scan.nextInt();
			      
			   }
	
		   


}

2）実例方法

2-1)オブジェクト向けの表現

2-2)表現を変える関数の形状