２段階目

em-oop/src/Day3Check2.java

@@ -0,0 +1,14 @@
+
+public class Day3Check2 {
+
+	public static void main(String[] args) {
+		Rectangle rectangle = new Rectangle(3,4);
+		
+		rectangle.showInfo();
+		System.out.println("四角形の面積は" + rectangle.area() + "です");
+		
+		Greeting greeting = new JapaneseGreeting();
+		
+		System.out.println(greeting.hello());
+	}
+}

em-oop/src/Greeting.java

@@ -0,0 +1,3 @@
+public interface Greeting {
+	String hello();
+}

em-oop/src/JapaneseGreeting.java

@@ -0,0 +1,9 @@
+
+public class JapaneseGreeting implements Greeting {
+	
+	@Override
+	public String hello() {
+		return "こんにちは";
+	}
+
+}

em-oop/src/Rectangle.java

@@ -0,0 +1,20 @@
+
+public class Rectangle extends Shape {
+	
+	private double width;
+	private double height;
+	
+	public Rectangle(double width, double height) {
+		super("四角");
+		this.width = width;
+		this.height = height;
+		
+	}
+
+	@Override
+	public double area() {
+		// TODO 自動生成されたメソッド・スタブ
+		return width * height;
+	}
+
+}

em-oop/src/Shape.java

@@ -1,5 +1,5 @@
 
-public class Shape {
+public abstract class Shape {
 
 	private String name;
 	
@@ -8,13 +8,13 @@ public class Shape {
 		
 	}
 	
-	public double area() {
-		return 0.0;
+	public abstract double area();
+		//return 0.0;
+		
 	
-	}
 	
 	public void showInfo() {
-		System.out.println(this.name + "の面積は" + this.area() + "です");
+		//System.out.println(this.name + "の面積は" + this.area() + "です");
 		
 	}
 }