尝试打印类变量时收到错误

Question

package mydate;

public class MyDate {

  private int day=1;
  private int month=1;
  private int year=2000;

public MyDate(int day,int month,int year)
{
  this.day=day;
  this.month=month;
  this.year=year;
  System.out.println(day+"  "+month+"  "+year);
}  
 System.out.println(day+"  "+month+"  "+year);// I am getting an error on this line saying cannot find symbol.How to print class variables of MyDate?

}

---

package mydate;

public class TestMyDate {

public static void main(String[] args) {
 MyDate today=new MyDate(22,7,1964); 
}
}

Answer 1

因为在一个类中你不能有一个print语句。仅限于功能！

Answer 2

此行System.out.println(day+" "+month+" "+year);// I am getting an error on this line saying cannot find symbol. How to print class variables of MyDate?必须位于类或构造函数的方法中。你不能把它粘在类定义的任何地方。我会把它放在一个方法而不是一个构造函数中，如下所示：

例如：

 public void printDate() {
     System.out.println(day+"  "+month+"  "+year);// I am getting an error on this line saying cannot find symbol. How to print class variables of MyDate? 
 }

然后，在main（）中，您可以在对象引用上调用该方法：

 MyDate today=new MyDate(22,7,1964);  
 today.printDate();

Answer 3

你不能在课堂上有自由浮动的陈述。尝试类似：

public void printInfo() {
    System.out.println(day+"  "+month+"  "+year);
}

然后你可以做

MyDate today=new MyDate(22,7,1964);
today.printInfo();

Answer 4

从Class.It中删除System.out.println将正常工作。