public class ch4_2 {

public class Rectangle{

public int x1,x2,y1,y2;

public Rectangle(){}

public Rectangle(int x1,int y1, int x2,int y2){

this.x1=x1;

this.x2=x2;

this.y1=y1;

this.y2=y2;

}

void set(int x1, int y1, int x2, int y2){

this.x1=x1;

this.x2=x2;

this.y1=y1;

this.y2=y2;

}

void show(){

int s ;

s = (x1-x2)*(y1-y2);

if(s<0)

s*=-1;

System.out.println("사각형의 넓이 " + s);

System.out.println("좌표 x1 >> " + x1 + "좌표 y1 >> "+ y1 +"좌표 x1 >> " + x2 + "좌표 y2 >> "+ y2);

}

int square(){

int s ;

s = (x1-x2)*(y1-y2);

if(s<0)

s*=-1;

return s; 

}

// boolean equals(Rectangle r){

// if(r == )

//}

}

public static void main(String[] args) {

Rectangle r = new Rectangle();  <- 여기가 no enclosing instance 에러가 나요 

Rectangle s = new Rectangle(1,1,2,3);

r.show();

s.show();

System.out.println(s.square());

r.set(-2,2,-1,4);

r.show();

System.out.println(r.square());

//if(r.equals(s))

//System.out.println("두 사각형은 같습니다");

}

}