１段階目

em-oop/src/Book.java

@@ -3,5 +3,18 @@ public class Book {
 	String title;
 	String author;
 	int price;
+	
+	public Book() {
+		title = "タイトル未設定";
+		author = "著者未設定";
+		price = 0;
 
+	}	
+	
+	public Book(String title,String author,int price){
+		
+		this.title = title;
+		this.author = author;
+		this.price = price;
+	}
 }