public class test{
public static void main(String[] args){
Book bk = new Book();
bk.sop();
}
}
class Book{
public int num = 4;
public void sop(){
//1.封装在类的方法里面的输出
System.out.println(this.num);
}
//2.类里直接使用输出语句
System.out.println("haha");
}