7월9일 JAVA(학점관리,도서관리예외처리)

import java.io.*;
import java.util.*;
public class uni{
  public static void main(String []args)throws IOException{
   BufferedReader stdin = new BufferedReader  //입력받는부분
                            (new InputStreamReader (System.in));
  int state,sub; //선택select 숫자
  String sname,smajor; //이름 , 전공
  String snumber;  //학번
  Vector str = new Vector(); //벡터생성
  while(true)
  {
    System.out.println("1. 입력");
    System.out.println("2. 출력");
    System.out.println("3. 종료");
    state=Integer.parseInt(stdin.readLine());//입력
    System.out.flush();    //입력버퍼비우기
    
    switch(state)
    {
    case 1:
      while(true)
      {  
        System.out.println("****입력모드****");
        System.out.println("\t 1. 학부생");  
        System.out.println("\t 2. 대학원생");  
        System.out.println("\t 3. 종료 ");  
        System.out.print("choose : ");
        sub=Integer.parseInt(stdin.readLine());
        System.out.flush();
        if(sub==3)
        {
          break;
        }
           
        switch(sub)
        {
          case 1:
          System.out.print("\t이름 : ");
          sname = stdin.readLine();
          System.out.flush();  
          
          System.out.print("\t학번 : ");  
          snumber =stdin.readLine();
          System.out.flush();  

          System.out.print("\t전공 : ");  
          smajor = stdin.readLine();
          System.out.flush();  
          
          department dep = new department(sub,sname,snumber,smajor);
          System.out.print("\tDB 성적 : ");  
          dep.DB =Double.parseDouble(stdin.readLine());
          System.out.print("\tOS 성적 : ");  
          dep.OS =Double.parseDouble(stdin.readLine());
          System.out.print("\tNW 성적 : ");  
          dep.NW =Double.parseDouble(stdin.readLine());
          dep.recode();
          dep.CDB=dep.averg(dep.DB);
          dep.CNW=dep.averg(dep.NW);
          dep.COS=dep.averg(dep.OS);
          dep.sum=dep.sumall(dep.DB,dep.NW,dep.OS);
          
          dep.CALL=dep.averg(dep.sum/3);
          str.addElement(dep);
          
          break;
          case 2:
          System.out.print("\t이름 : ");
          sname = stdin.readLine();
          System.out.flush();  
          
          System.out.print("\t학번 : ");  
          snumber =stdin.readLine();
          System.out.flush();  

          System.out.print("\t전공 : ");  
          smajor = stdin.readLine();
          System.out.flush();  

          superdepart sep = new superdepart(sub,sname,snumber,smajor);
          System.out.print("\tDB 성적 : ");  
          sep.DB =Double.parseDouble(stdin.readLine());
          System.out.print("\tOS 성적 : ");  
          sep.OS =Double.parseDouble(stdin.readLine());
          System.out.print("\tNW 성적 : ");  
          sep.NW =Double.parseDouble(stdin.readLine());
          sep.recode();
          sep.CDB=sep.averg(sep.DB);
          sep.CNW=sep.averg(sep.NW);
          sep.COS=sep.averg(sep.OS);
          sep.sum=sep.sumall(sep.DB,sep.NW,sep.OS);
          sep.CALL=sep.averg(sep.sum/3);
          str.addElement(sep);
    
          
          break;
          
        }
        
      }
    break;

    case 2:
  
    if((str.isEmpty())!=false)
    {  
            System.out.println("검색되는 학생이없습니다");
            break;
    }  
    System.out.println("********학생정보********");
    System.out.println("정보\t이름\t학번\t전공\t  DB\t  OS\t  NW\t총점\t평점");
    for(int i=0 ;i<str.size();i++)
         {  
      ((StudentInformation)str.get(i)).print();       
          }  
    
    break;
    
    case 3:
      System.out.println("종료합니다.....");
    return ;
    }
    
  }


  }

}
interface addition
{
  double NW_OS_BALL= 0.05; //학부생 가산점
  double DB_PLUS =0.2;  //대학원생 가산점  

}
class StudentInformation  implements addition//학생정보
{
  protected String name; //이름
  protected int state;  //학부/대학원생
  protected String number;//학번
  protected String major,hagbu; // 전공//학부//대학원생
  protected  String CDB,COS,CNW,CALL; //각 수업 성적(A+...)
  protected double DB; //DB성적
  protected double OS;  //OS성적
  protected double NW;  //NW성적
  public double sum;  //성적합계
  
  StudentInformation(int astate,String sname, String inumber, String smajor,String ahagbu)
  { //생성자
    name = sname;
    number = inumber;
    major = smajor;  
    state = astate;
    hagbu =ahagbu;
     
  }
  protected void print()
  {
    //출력
    
    System.out.print(hagbu+"\t");
    System.out.print(name+"\t");
    System.out.print(number+"\t");
    System.out.print(major+"\t");
    System.out.print(DB);
    System.out.print("["+CDB+"]");
    System.out.print(" "+OS);
    System.out.print("["+COS+"]");
    System.out.print(" "+NW);
    System.out.print("["+CNW+"]");
    System.out.print(" "+sum+"\t");
    System.out.println(CALL);


  }
  public void recode() //학과비교 가산점
  {
    if(this.major.equals("컴공"))
    {
      this.NW =this.NW+this.NW*NW_OS_BALL;
    }
    else if(this.major.equals("컴과"))
    {
      this.OS = this.OS+this.OS*NW_OS_BALL;
    }
  }
  public String averg(double avr) //성적출력
  {  
    if((avr>=95)) return "A+";
    else if((avr<95)&&(avr>=90)) return "A";
    else if((avr<90)&&(avr>=85)) return "B+";
    else if((avr<85)&&(avr>=80)) return "B";
    else if((avr<80)&&(avr>=70)) return "C";
    else if((avr<70)&&(avr>=60)) return "D";
    else if((avr<60)&&(avr>=0)) return "F";
    return "-F";
  }
  public double sumall(double a,double b,double c) //총점
  {
    return a+b+c;

  }
  

}
class department extends StudentInformation //학부
{
  private String hagbu="학부";
  public department(int astate,String sname,String inumber, String smajor)
  {  
    super(astate,sname,inumber,smajor,"학부");
    
    
  }
  protected void print() //출력
  {
  
    
    System.out.print(hagbu+"\t");
    System.out.print(name+"\t");
    System.out.print(number+"\t");
    System.out.print(major+"\t");
    System.out.print(DB);
    System.out.print("["+CDB+"]");
    System.out.print(" "+OS);
    System.out.print("["+COS+"]");
    System.out.print(" "+NW);
    System.out.print("["+CNW+"]");
    System.out.print(" "+sum+"\t");
    System.out.println(CALL);

  }
  public void recode() //전공비교
  {
    if(this.major.equals("컴공"))
    {
      this.NW =this.NW+this.NW*NW_OS_BALL;
    }
    else if(this.major.equals("컴과"))
    {
      this.OS = this.OS+this.OS*NW_OS_BALL;
    }
  }
  
  
  
}
class superdepart extends StudentInformation //대학원
{  
  private String hagbu="대학원";
  public superdepart(int astate,String sname,String inumber, String smajor)
  {  
    super(astate,sname,inumber,smajor,"대학원");
    
  }
  protected void print()
  {
  
  
    System.out.print(hagbu+"\t");
    System.out.print(name+"\t");
    System.out.print(number+"\t");
    System.out.print(major+"\t");
    System.out.print(DB);
    System.out.print("["+CDB+"]");
    System.out.print(" "+OS);
    System.out.print("["+COS+"]");
    System.out.print(" "+NW);
    System.out.print("["+CNW+"]");
    System.out.print(" "+sum+"\t");
    System.out.println(CALL);

  }
  public void recode()
  {
    if(this.major.equals("NW"))
    {
      this.NW =this.NW+this.NW*DB_PLUS;
    }
    else if(this.major.equals("OS"))
    {
      this.OS = this.OS+this.OS*DB_PLUS;
    }
    else if(this.major.equals("DB"))
    {
      this.DB = this.DB+this.DB*DB_PLUS;
    }
  }
  


}
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예외처리에서는 Throwable 클래스에서 파생되는 Error클래스와
Exception클래스가 잇다.  그리고 그밑에서는 여러가지 예외가 있고
처리할수가 있다.

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7장 연습문제 5장의 도서관리를 예외처리로 바꾸서 다시 만들었다.
import java.io.*;
import java.util.*;

class Library {
  public static void main(String[] args) throws IOException {
    BufferedReader stdin = new BufferedReader(new InputStreamReader(
        System.in));
    Vector Booklist = new Vector(5, 5);
    int istate = 0; // 선택 변수
    String sname;
    String swri;
    String scom;
    int ipri=0;
    int i;
    int a = -1;
    int b = -1;
    while (true) {
      try
      {
      System.out.println("****원하는 서비스를 선택하세요****");
      System.out.println();
      System.out.println("\t1. Search Book.");
      System.out.println("\t2. Add Book.");
      System.out.println("\t3. Delete Book.");
      System.out.println("\t4. List Book.");
      System.out.println("\t5. Quit");
      System.out.println();
      System.out.print("Number :");
      istate = Integer.parseInt(stdin.readLine());
      System.out.flush();
      System.out.println();
        if(istate>5||istate<1)
        {
        
          throw new MyException("throw an Exception");
          
        }
      }catch(NumberFormatException exp)
      {
        System.out.println("숫자로 입력하세요");
      }catch(MyException exp)
      {
        System.out.println("1~5사이의 숫자로입력하세요");
      }
      switch (istate) {
      case 2: // 추가
        System.out.println();
        System.out.println("Adding Book!");
        System.out.println();
        System.out.print("\tBook Name : ");
        sname = stdin.readLine();
        System.out.flush();

        System.out.print("\tAuthor : ");
        swri = stdin.readLine();
        System.out.flush();

        System.out.print("\tPublisher : ");
        scom = stdin.readLine();
        System.out.flush();
        while(true)
          {
            
              try
              {
              
              System.out.print("\tPrice : ");
              ipri = Integer.parseInt(stdin.readLine());
              Integer Int = new Integer(ipri);
              System.out.flush();
              if(Int.equals(ipri))
              {  
                break;
              }

              }catch(NumberFormatException axp)
              {
              System.out.println("숫자로 다시입력하세요");
              }
                            
              
              
          }
        
        
        
        
        BOOK bk = new BOOK(sname, swri, scom, ipri);
        Booklist.addElement(bk.bookname);
        Booklist.addElement(bk.writer);
        Booklist.addElement(bk.company);
        Booklist.addElement(bk.price);
        break;

      case 1: // 검색
        System.out.println();
        System.out.println("Searching Book!");
        System.out.println();
        System.out.print("\tBook Name : ");
        sname = stdin.readLine();
        System.out.flush();

        a = Booklist.indexOf(sname);
        if (a != -1) {

          System.out.println("=========검색==============");
          System.out
              .println("\tBook Name : " + Booklist.elementAt(a));
          System.out.println("\tAuthor : "
              + Booklist.elementAt(a + 1));
          System.out.println("\tPublisher : "
              + Booklist.elementAt(a + 2));
          System.out
              .println("\tPrice : " + Booklist.elementAt(a + 3));
          System.out.println("===========================");

        } else {
          System.out.println("검색되는 책이없습니다");
        }

        break;

      case 3: // 삭제
        System.out.println();
        System.out.println("Deleting Book!");
        System.out.println();
        System.out.print("\tBook Name : ");
        sname = stdin.readLine();
        System.out.flush();

        a = Booklist.indexOf(sname);

        System.out.println(a);

        Booklist.remove(Booklist.get(a)); // remove될때 반이 되면.. 자동으로 순서가
                          // 바뀐다.
        Booklist.remove(Booklist.get(a + 1));
        Booklist.remove(Booklist.get(a));
        Booklist.remove(Booklist.get(a));
        break;

      case 4: // 전체검색
        if ((Booklist.isEmpty()) != false) {
          System.out.println("검색되는 책이없습니다");
          break;
        }
        System.out.println("=========검색==============");
        for (i = 0; i < Booklist.size(); i = i + 4) {
          System.out
              .println("\tBook Name : " + Booklist.elementAt(i));
          System.out.println("\tAuthor : "
              + Booklist.elementAt(i + 1));
          System.out.println("\tPublisher : "
              + Booklist.elementAt(i + 2));
          System.out
              .println("\tPrice : " + Booklist.elementAt(i + 3));
          System.out.println("===========================");

        }
        break;

      case 5:
        System.out.println("종료합니다");
        return;
      
      }
    }

  }
}

class BOOK {
  String bookname;
  String writer;
  String company;
  int price;

  public BOOK(String bo, String wr, String co, int pr) {
    bookname = bo;
    writer = wr;
    company = co;
    price = pr;
  }
}

class MyException extends Throwable {
  public MyException() {
  }; // default 생성자

  public MyException(String myMessage) {
    super(myMessage);
  }
}