在JOptionPane中進行確認，我可以循環回到掃描儀嗎？

Question

我是新手，如果我有點慢，請原諒我。

如果我有一個JOptionPane的確認對話框，可以循環回掃描器如果用戶狀態是？ EX：在JOptionPane中，如果用戶回答是，那么我就希望回過頭來，要求電力和實驗，並調用方法的結果 - 不斷重復，直到用戶確認NO。 那有意義嗎？

我的完整代碼如下。

import java.util.Scanner;
import javax.swing.JOptionPane;

 public class XtoNthPowerRecursively {

//Main method
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter base to be raised to power: ");
double Base = input.nextDouble();

System.out.print("Enter exponent to raise base to: ");
int Exp = input.nextInt();
  if (Exp < 0) {
      System.out.print("Exponent cannot be negative. Re-enter: ");
      Exp = input.nextInt();
  }

//Print Base and Exp with result
System.out.println("Base " + Base + " raised to the power " + Exp + " is " + power(Base, Exp));

//JOptionPane confirmation dialog
int n = JOptionPane.showConfirmDialog(null,"Would you like to enter another base and power?", "Confirmation",JOptionPane.YES_NO_OPTION);
  if(n == JOptionPane.YES_OPTION)
  {
      JOptionPane.showMessageDialog(null,"Let's start");
  }
  else
  {
      JOptionPane.showMessageDialog(null,"Goodbye");
  }
  }

//Calling pow method
  public static double power(double Base, int Exp) {
if (Exp < 0 ) {
    return power(Base, ++Exp)/Base;
} else if (Exp == 0) {
    return 1.0;
} else {
    return power(Base, --Exp) * Base;
}
  }
}

Answer 1

您可以將所有與用戶輸入直接相關的代碼（而不是pow方法）封裝在while循環中，終止條件類似於boolean carryOn = false 。例如，

while (carryOn)
{
    Do your code here.
    Show the dialog box.
    If (userInput.equalsIgnoreCase("no"))
        carryOn = false;
        System.out.println("Goodbye"); // The loop terminates.
    else if (userInput.equalsIgnoreCase("yes"))
        carryOn = true;
        // User is returned to the start of the loop to enter another number.
}

您還可以將if/else語句也包含在循環中，以確保只有yes和no是有效的響應，並且其他任何原因都會導致對話框再次出現...

您還需要對第一段代碼做一些工作。 您檢查用戶輸入的數字是否小於數字，然后立即致電掃描儀。 這意味着將檢查第一個數字，但是第二個數字將被接受。

Answer 2

在do-while循環中運行代碼，直到用戶單擊“否”

 do{
    Scanner input = new Scanner(System.in);
    System.out.print("Enter base to be raised to power: ");
    double Base = input.nextDouble();

   System.out.print("Enter exponent to raise base to: ");
   int Exp = input.nextInt();
   if (Exp < 0) {
      System.out.print("Exponent cannot be negative. Re-enter: ");
      Exp = input.nextInt();
   }

   //Print Base and Exp with result
   System.out.println("Base " + Base + " raised to the power " + Exp + " is " + power(Base, Exp));

   //JOptionPane confirmation dialog
   int n = JOptionPane.showConfirmDialog(null,"Would you like to enter another base and power?", "Confirmation",JOptionPane.YES_NO_OPTION);
   if(n == JOptionPane.YES_OPTION) {
      JOptionPane.showMessageDialog(null,"Let's start");
   } else {
      JOptionPane.showMessageDialog(null,"Goodbye");
   } 
}while (n != JOptionPane.NO_OPTION)

Answer 3

感謝大家。 我決定調用一個方法而不是一個do-while循環。 最終代碼如下。

public class XtoNthPowerRecursively 
//Main method
public static void main(String[] args) {
run ();
}

public static void run() { 
Scanner input = new Scanner(System.in);
System.out.print("Enter base to be raised to power: ");
double Base = input.nextDouble();

System.out.print("Enter exponent to raise base to: ");
int Exp = input.nextInt();
while (Exp < 0) {
  System.out.print("Exponent cannot be negative. Re-enter: ");
  Exp = input.nextInt();
}

    //Print Base and Exp with result
System.out.println("Base " + Base + " raised to the power " + Exp + " is " + power(Base, Exp));

//JOptionPane confirmation dialog
int n = JOptionPane.showConfirmDialog(null,"Would you like to enter another base and power?", "Confirmation",JOptionPane.YES_NO_OPTION);
if(n == JOptionPane.YES_OPTION)
{
  JOptionPane.showMessageDialog(null,"Let's start");
  run ();
}
else
{
  JOptionPane.showMessageDialog(null,"Goodbye");
}
}