myRectangle.calculateArea(); returns 错误 "package myRectangle does not exist"

Question

矩形

public class Rectangle {

  private double width;
  private double length; 


public Rectangle(double L, double W){
  length = L;
  width = W;
}

public void setLength(double Length){
  if (length>=0 && length <=20)
    length = Length;
else{
  length = 0;
}
}
public double getLength(){
  return length;
}
public void setWidth(double Width){
  if (width>=0 && length <=20)
    width = Width;
else{
    width = 0;
}
}
public double getWidth(){
  return width;
}

public void calculatePerimeter(){
  System.out.println("The perimeter of rectangle is: " + 2 * (length + width));
}
public void calculateArea(){
  System.out.println("The area of the rectangle is: " + (length * width));
}
}

测试矩形

import java.util.Scanner;

public class TestRectangle {
public static void main(String[] args){

Scanner input = new Scanner(System.in);
  Rectangle myRectangle = new Rectangle (0,0);//I did the same thing in a 
//previous assignment, and someone else who did this assignment (code found 
//online) also did this. It worked before but seems useless now?

System.out.println("Enter length: ");
  double L = input.nextDouble();
  System.out.println();

System.out.println("Enter width: ");
  double W = input.nextDouble();
  System.out.println();
}
myRectangle.calculateArea();//here
myRectangle.calculatePerimeter();//and here is where I get the error
//<identifier> expected, package myRectangle does not exist
}

我正在尝试创建一个程序“Rectangle”来计算矩形的面积和周长，然后创建一个测试程序来运行程序“Rectangle” 我从之前的一个名为“Date”的作业中复制了代码，其中的基本思想是相似的，但是当我到达程序末尾时我需要调用“calculateArea();”和“计算周长（）；”在测试程序中，我收到一条错误消息，告诉我包 myRectangle 不存在……有人能告诉我为什么会这样吗？一个类似的代码在之前的作业中起作用，我发现其他人的代码用于相同的“Rectangle”程序并且它显示相同的错误。是我做错了什么还是我的 NetBeans 有问题？

这是我基于 的 Rectangle 和 TestRectangle 程序的代码日期

public class Date {
private int month;
private int day;
private int year;

public Date(int m, int d, int y){
    month = m;
    day = d;
    year = y;
}

public void setMonth(int Months){
    if(Months>=0 && Months <= 12)
        month=Months;
    else{
        month=0;
    }
}
public int getMonth(){
    return month;
}

public void setDay(int Days){
    if(Days>= 0 && Days<=31)
        day = Days;
        else{
                day=0;
                }
}

public int getDay(){
    return day;
}

public void setYear(int Years){
    year=Years;
}
public int getYear(){
    return year;
}
public void displayDate(){
    System.out.printf
            ("%d/%d/%d\n", getMonth(), getDay(), getYear() );
}
}

测试日期

import java.util.Scanner;

public class DateTest {
public static void main(String[] args){
  Scanner input = new Scanner(System.in);

Date myDate = new Date(0,0,0);

System.out.println("Justine Dodge, assignment 6\n");


System.out.println("Please enter month: ");
  int m = input.nextInt();
  myDate.setMonth(m);
  System.out.println();


System.out.println("Enter day: ");
  int d = input.nextInt();
  myDate.setDay(d);//assign d to Day?
  System.out.println();//output blank line

System.out.println("Enter year: ");
  int y = input.nextInt();
  myDate.setYear(y);
  System.out.println();


myDate.displayDate();

}
}

Answer 1

在 TestRectangle 中，您将在调用这些函数之前关闭 main 方法

} // this should be at at the end of the main function 
myRectangle.calculateArea();//here
myRectangle.calculatePerimeter();//and here is where I get the error

即

myRectangle.calculateArea();//here
myRectangle.calculatePerimeter();//and here is where I get the error
}

这将消除编译错误。现在当你运行它时，你会得到面积和周长都为 0，因为在构造函数中，你将长度和宽度的值作为 0 传递，而不是真正使用作为输入的长度和宽度。要解决此问题，请不要在构造函数中传递 0,0，尝试像这样在构造函数中传递 L,W


  Rectangle myRectangle = new Rectangle (L,W);
myRectangle.getLength()); //
myRectangle.calculateArea();//here
myRectangle.calculatePerimeter();


import java.util.Scanner;

public class TestRectangle {
public static void main(String[] args){

Scanner input = new Scanner(System.in);
//  Rectangle myRectangle = new Rectangle (0,0);//I did the same thing in a 
//previous assignment, and someone else who did this assignment (code found 
//online) also did this. It worked before but seems useless now?

System.out.println("Enter length: ");
  double L = input.nextDouble();
  System.out.println();

System.out.println("Enter width: ");
  double W = input.nextDouble();
  System.out.println();

  
  Rectangle myRectangle = new Rectangle (L,W);
//  System.out.println("get length " + myRectangle.getLength());
myRectangle.calculateArea();//here
myRectangle.calculatePerimeter();//and here is where I get the error
//<identifier> expected, package myRectangle does not exist
}
}

那么你会得到 o/p 这样的

myRectangle.calculateArea(); returns 错误 "package myRectangle does not exist"

myRectangle.calculateArea(); returns error "package myRectangle does not exist"

java

netbeans

method-call