<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script>
class Area {
constructor(width, height, radius){
this._width = width;
this._height = height;
this._radius = radius;
}
}
Area.prototype.area = '';
class Rectangle extends Area{ //extends 했을 때 super는 예약어다.
constructor(width, height)
{
super(width, height);
}
set width(width){
this._width = width;
}
set height(height){
this._height = height;
}
}
Rectangle.prototype.area = function(){
return alert("넓이는 " + (this._width * this._height) + "입니다.")
}
class Square extends Rectangle{
constructor(width)
{
super(width);
}
set width(width){
this._width = width;
}
}
Square.prototype.area = function(){
return alert("넓이는 " + (this._width * this._width) + "입니다.")
}
class Triangle extends Area{
constructor(width, height)
{
super(width, height);
}
set width(width){
this._width = width;
}
set height(height){
this._height = height;
}
}
Triangle.prototype.area = function(){
return alert("넓이는 " + (this._width * this._width * 0.5) + "입니다.")
}
class Circle extends Area{
constructor(radius)
{
super();
this._radius = radius;
}
set radius(radius){
this._radius = radius;
}
}
Circle.prototype.area = function(){
return alert("넓이는 " + (3.141592 * this._radius * this._radius) + "입니다.")
}
var num = parseInt(prompt("도형을 선택하세요 1: 직사각형, 2: 정사각형, 3: 삼각형, 4: 원"));
switch(num){
case 1 :
var width = parseFloat(prompt("가로 길이"));
var height = prompt("세로 길이");
let recArea = new Rectangle(width, height);
recArea.area();
break;
case 2 :
var width = parseFloat(prompt("길이"));
let squArea = new Square(width);
squArea.area();
break;
case 3 :
var width = parseFloat(prompt("밑변"));
var height = parseFloat(prompt("높이"));
let triArea = new Triangle(width, height);
triArea.area();
break;
case 4 :
var radius = parseFloat(prompt("반지름"));
let cirArea = new Circle(radius);
cirArea.area();
break;
}
</script>
</head>
<body>
</body>
</html>
