학생 정보 출력 (추상클래스)

public abstract class Student {

private int id;

private int tuition;

private double gpa;

 

public void setTuition(int tuition) {this.tuition = tuition;};

public void setGpa(double gpa) {this.gpa = gpa;};

public int getId() {return id;};

public int getTuition() {return tuition;};

public double getGpa() {return gpa;};

 

public abstract int clacScholarship();

 

public String toString() {//public 지울 수 있다. protect로!!, private는 오류 발생

return "학번: " + id + ", 등록금: " + tuition + ", 평균등급: " + gpa + ", 장학금: " + clacScholarship();

  }

 

public Student () {

this.id = 0;

this.tuition = 0;

this.gpa = 0;

  }

 

public Student (int id, int tuition, double gpa) {

this.id = id;

this.tuition = tuition;

this.gpa = gpa;

  }

}

 

 

 

public class Graduate extends Student{

private String lab;

 

public void setLab(String lab) {this.lab = lab;};

 

public String getLab() {return lab;};

 

public int clacScholarship() {

if (getGpa() >= 3.5) {

return getTuition() / 2;

} else {

return getTuition() / 10;

}

  }

 

public String toString() {

return super.toString() + ", 연구실: " + lab;

  }

 

public Graduate() {

super();

this.lab = "None";

 }

 

public Graduate(int id, int tuition, double gpa, String lab) {

super(id, tuition, gpa);

this.lab = lab;

  }

}

 

 

public class Undergraduate extends Student{

private int year;

 

public void setYear(int year) {this.year = year;};

public int getYear() {return year;};

 

public int clacScholarship() {

return getTuition() * 3 / 10;

  }

 

public String toString() {

return super.toString() + ", 학년: " + year;

  }

 

public Undergraduate() {

super();

this.year = 0;

  }

 

public Undergraduate(int id, int tuition, double gpa, int year) {

super(id, tuition, gpa);

this.year = year;

  }

}

 

 

 

public class VisitingStudent extends Student{

public int clacScholarship() {

return 0;

  };

 

public VisitingStudent(int id, int tuition, double gpa) {

super(id, tuition, gpa);

  }

}

 

 

public class Practice_78 {

 

public static void main(String[] args) {

//Student S1 = new Student(1111, 100, 3.2); 추상클래스는 객체를 만들 수 없다.

Undergraduate S2 = new Undergraduate(2222, 100, 4.1, 3);

Graduate S3 = new Graduate(3333, 100, 3.4, "SE");

Graduate S4 = new Graduate(5555, 100, 4.0, "OS");

VisitingStudent S5 = new VisitingStudent(4444, 100, 2.5);

 

//System.out.println(S1.toString());

System.out.println(S2.toString());

System.out.println(S3.toString());

System.out.println(S4.toString());

System.out.println(S5.toString()); 

 }

}

 

 

결과: