[JAVA] 상속에 대한 기본 예제

package a;
 
class Calculator {
    int left, right;
 
    public void setOprands(int left, int right) {
        this.left = left;
        this.right = right;
    }
 
    public void sum() {
        System.out.println(this.left + this.right);
    }
 
    public void avg() {
        System.out.println((this.left + this.right) / 2);
    }
}
 
class SubstractionableCalculator extends Calculator {
//extends Calculator 를 통해서 상속을 받음
    public void substract() {
        System.out.println(this.left - this.right);
    }
//substract라는 메소드를 추가
}
 
public class CalculatorDemo1 {
 
    public static void main(String[] args) {
 
        SubstractionableCalculator c1 = new SubstractionableCalculator();
        c1.setOprands(10, 20);
        c1.sum();
        c1.avg();
        //상속을 받았으므로 setOperands,sum,avg 메소드를 사용 할 수 있음
        c1.substract();
    }
 
    
}