java - 使用 boolean 值创建选项 >reserved<？

Question

好吧，我的程序“完成”了，但我无法解决这个简单的问题。

我得到了这个:

package hotel;
import java.util.Scanner;
/**
*
* @author Defalt
*/
public class Hotel {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    Prices prices = new Prices();
    Scanner user_in = new Scanner(System.in);
    String method;
    boolean taken = false;
    boolean taken2 = false;
    boolean taken3 = false;
    boolean again = true;

    //***********Introduction to the hotel*************

    System.out.println("Welcome to Hotel Vermond's Heaven!");
    System.out.println("We are happy to see that you would like to stay with us.");

    //***********Creating of a Loop*************


    do {
    System.out.println("Please, type which room you would like to book: ");
    System.out.println("Single Bed, Double Bed, President Suit");
    method = user_in.nextLine();

    //***********Choices of Rooms and Question to book another one*************

    if ("Single Bed".equals(method)) {
            System.out.println(prices.describe1());
    if ("y".equals(user_in.nextLine())){
         if(taken=true){
                System.out.println("We are sorry, this room is already booked. Please choose another one");
            }else again=true;
    } else again=true;
        } else if ("Double Bed".equals(method)){
            System.out.println(prices.describe2());
    if ("y".equals(user_in.nextLine())){
            taken2 = true;
            again=true;
        } else again=true;
    } else if ("President Suit".equals(method)){
            System.out.println(prices.describe3());
    if ("y".equals(user_in.nextLine())){
            taken3 = true;
            again=true;
    } else again=true;

    } else {
            System.out.println("Please choose one of the rooms above.");
    }
            System.out.println("Would you like to book another Room(y/n)\n");

    //***********Outbreak if User declines another booking*************
    //***********Otherwise redo the whole process************* 

    if ("y".equals(user_in.nextLine())){
        again=true;
    } else{
        break;
    }
 }while(again);
    System.out.println("Thank you and goodbye!");

   }
}

我的另一个类(class)是这样的:

package hotel;
import java.util.Scanner;
/**
*
* @author Defalt
*/
public class Prices {
Scanner user_in = new Scanner(System.in);
int price1 = 300;
int price2 = 800;
int price3 = 2500;

//***********Information of the Room including Validation Question*************

public String describe1() {  
       return
        "You Choose the Single Bed.\n\tThis room Contains 1 Bed, 1 Fridge a Bathroom but no View on the Ocean.\n\tThis room will cost CHF " + price1 + ".-.\n\tWould you like to book this room?(y/n)";
   }
public String describe2() {  
   return
    "You Choose the Double Bed.\n\tThis room Contains 1 Queen-size Bed, 1 Fridge a bathroom, an Icemaker but no View on the Ocean.\n\tThis room will cost CHF " + price2 + ".-.\n\tWould you like to book this room?(y/n)";
   } 
public String describe3() {  
   return
    "You Choose the President Suit.\n\tThis room Contains 1 King-size Bed, 1 Fridge, XXL Bathroom, Private Entertainment-System, 65inch Flatscreen and a Balcony with View on the Ocean.\n\tThis room will cost CHF " + price3 + ".-.\n\tWould you like to book this room?(y/n)";
   } 
}

如您所见，在单人床被预订后，我试图将其设为保留房间。然而，即使在第一次预订时也会显示 System.out.println(“抱歉，此房间已被预订。请选择另一个房间”); 。

为什么即使我的 taken boolean 值的初始值为 false？ 我还可以采取哪些其他选择来实现我的想法？

PS!:我想我第一次就成功了，但是无论我关闭程序并重新启动它的频率如何，它都会保持所取值为true。 (只是旁注)

Answer 1

你需要改变

if(taken=true){
            System.out.println("We are sorry, this room is already booked. Please choose another one");

至

if(taken==true){
            System.out.println("We are sorry, this room is already booked. Please choose another one");

注意 if 条件中的 double 等于。这将检查 taken 的值，而不是总是将其设置为 true，这就是当前正在发生的情况。

或者，由于 taken 已经是一个 boolean 值，您可以将其简化为:

if(taken){
            System.out.println("We are sorry, this room is already booked. Please choose another one");

如果您修复了格式和缩进，可能会帮助您解决这些问题。我倾向于避免在任何时候省略花括号。这通常是 java 标准格式:

if(condition) {
    if(condition) {
        // do the thing
    }
    else {
        // do the other thing
    }
}
else if(condition) {
    // do another thing
}
else {
    // do the third thing
}

请注意同一嵌套级别的 ifs/else ifs/else 是如何保持相同的缩进级别的。这对于保持直线有很大帮助。

编辑:

我想指出的另一件事是，您有 again boolean 值，但您没有使用它。如果用户完成，不要break跳出循环，而是使用您应该使用的again boolean 值并将其设置为 false。这将导致循环条件失败并很好地退出循环。使用break 很难看。