如何在 for 循环中更改之前显示值

Question

" 程序应首先询问属性有多少个房间。使用循环计算每个房间的矩形面积 (SQF)。显示每个房间的 SQF 和房间的总 SQF 属性.

所以，我终于让我的代码工作了，除了我无法得到一件事：问题示例：假设我进入 2 个房间，然后对于第一个房间，我输入 10 x 2，即面积 20，然后对于第二个房间，我输入 8 x 2，即 16。好吧，当代码在最后显示信息时，它只显示 16 作为两个房间的面积，我假设这是因为这是最后计算的面积。最后它显示总面积为 36，所以我知道我接近正确的路径。但我一辈子都弄不明白。

import javax.swing.JOptionPane;
public class PropertySF
{
public static void main(String[] args)
{

   double length = 0,    // The room's length
          width = 0,     // The room's width
          area = 0;      // The room's area
   int numRoom;          // for number of rooms
   double roomSF = 0;    // square footage for each room
   double totalSF = 0;   // Total square footage



  // Get the amount of rooms
  numRoom = getRooms();

  // Get the rooms dimentions from the user.
  for (double maxRoom = 1; maxRoom <= numRoom; maxRoom++)
  {
      length = getLength();

      // Get the rooms's width from the user.
      width = getWidth();

      // Get the rooms's area.
      area = getArea(length, width);
      totalSF += area;
 }

  // Display the room data.
  displayData(numRoom, totalSF, area);

  System.exit(0);
}

public static int getRooms()
 {
   //See CL 5-10 Page 298
   String input;        //For input
   //get input from user
   input = JOptionPane.showInputDialog("Enter the number of rooms in the 
                                         the house: "); //Line 37
   return Integer.parseInt(input); //Line 45- 48
  }

/**
*The getLength prompts user for the length of the room
*@return value entered by user.
*/
public static double getLength()
{
   //See CL 5-10 Page 298
   String input;        //For input
   //get input from user
   input = JOptionPane.showInputDialog("Enter the length of the room:");
   return Double.parseDouble(input); //Line 45- 48
}

/**
*The getWidth prompts user for the Width of the room
*@return value entered by user.
*/
public static double getWidth()
{
   //See CL 5-10 Page 298
   String input;        //For input
   //get input from user
   input = JOptionPane.showInputDialog("Enter the width of the room:");
   return Double.parseDouble(input); //Line 45-48
} 

/**
* The getArea method will calculate the room's area
* @param length the room's length
* @param with the room's width
* @return the area of the room
*/
public static double getArea(double length, double width)
{
   return length * width;
}

/**
* The displayData method displays the rooms data.
* 
*/

public static void displayData(double numRoom,
                              double totalSF,
                              double area)
{
   for (double maxRoom  = 1; maxRoom <= numRoom; maxRoom++)
   {
   JOptionPane.showMessageDialog(null,
     String.format("The Square footage for room %f is %f,\n" +
                                "The total SQF is: %f \n", maxRoom, area,
 totalSF));
   }                             
 }

}

Answer 1

是的，area 只被传递给 displayData 函数一次，所以循环中只有一个值。一种可能的解决方案是传入一个区域数组，然后在循环遍历房间时循环遍历它，但我认为更好的解决方案是在 displayData 中一次只显示一个房间（因此从 displayData 中删除循环，并移动函数调用到 main 中的循环中）并将 totalSF 显示移动到另一个函数（如果您不想显示运行总的 totalSF）。

Answer 2

可能的解决方案是将区域定义为数组或list（如果大小未知），将值存储在数组中并显示它。虽然有几种方法可以做到这一点。

如何在 for 循环中更改之前显示值

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