SW공부 25일차

1. 아래가 돌아가도록 하시오.

main(){
    	Circle[] circleArr = new Circle[2];
    	circleArr[0] = new Circle(10);
    	circleArr[1] = new Circle(10);

    	//System.out.println(circleArr[0].getArea());
    	//System.out.println(circleArr[1].getArea());
    	    	
    	double areas = Circle.getArrArea(circleArr);
    	System.out.println(areas);
}

import java.util.Arrays;

public class Circle {

	private double r;
	private double area;
	private static double areas;

	public Circle(double r) {
		this.r = r;
	}

	private double area() {
		area = Math.pow(this.r, 2) * Math.PI;
		return area;
	}

	static double getArrArea(Circle[] circle) {
		for (int i = 0; i < circle.length; i++) {
			areas += circle[i].area();
		}
		return areas;
	}

}

2. 아래가 18이 나오도록 getStrArr 함수를 만드시오.

    	String[] strArr = new String[3];
    	
    	strArr[0] = "ABCDER";
    	strArr[1] = "ABCDER";
    	strArr[3] = "ABCDER";
    	
    	System.out.println(getStrArr(strArr));

	public static int getStrArr(String[] str) {
		int sum = 0;
		for (int i = 0; i < str.length; i++) {
			sum += str[i].length();
		}
		return sum;
	}

3. 아래가 나오도록 Rectangle 객체를 만드시오.

   	
    	Rectangle[] recArr = new Rectangle[2];
    	recArr[0] = new Rectangle(10,20);
    	recArr[1] = new Rectangle(10,30);

   	    	
    	double areas = Rectangle.getArrArea(recArr);
    	System.out.println(areas);

public class Rectangle {
	private double base;
	private double height;
	private double area;
	private static double addRrectangle;
	
	public Rectangle(double base, double height) {
		this.base = base;
		this.height = height;
	}
	
	private double area() {
		area = base * height;
		return area;
	}
	
	public static double getArrArea(Rectangle[] rectangle) {
		for (int i = 0; i < rectangle.length; i++) {
			addRrectangle += rectangle[i].area();
		}
		return addRrectangle;
	}
}

4.main 에서 실행된 Box[] ar = new Box[3] 대한 메모리 그림을 그리시오.

class Box {
   private String conts;
   
   Box(String cont) { this.conts = cont; }
   public String toString() {
      return conts;
   }
}

public static void main(String[] args) {
   Box[] ar = new Box[3];

   // 배열에 인스턴스 저장
   ar[0] = new Box("First");
   ar[1] = new Box("Second");
   ar[2] = new Box("Third");

   // 저장된 인스턴스의 참조
   System.out.println(ar[0]);
   System.out.println(ar[1]);
   System.out.println(ar[2]);
}