while 循环不适用于两个 if 语句

Question

我试过到处在线搜索，但我不能。基本上我想做一个程序，你可以选择你想要的饮料，然后当你输入饮料时，它会告诉你有多少。我使用了一个 while 循环，所以如果你输入错误的价格，它会一直要求正确的价格，直到你 select 它。它适用于我的第一杯饮料 "pepsi" 但是当我选择可乐时，代码根本就没有运行.. 它甚至不询问价格。

import java.util.Scanner;
public class BendingMachineTestWhile{



 public static void main (String [] args)
  {
    String drink;
    int money;
    Scanner kbd = new Scanner (System.in);

System.out.println (" Pick from the following drinks: \n pepsi \n coke \n gatorade");
drink = kbd.nextLine();
while (true){     
  if (drink.equals ("pepsi"))
  {
    System.out.println ("That will be 4 dollars");
    System.out.println ("Enter 4 dollars");
    money = kbd.nextInt();
    if ( money == 4 )
    {
      System.out.println ("Thanks.");
      break;
    }
    else if ( money != 4)
    {
      System.out.println ("You idiot its four dollars");
    }

  }
}

if (drink.equals ("coke"))
{
  System.out.println ("That will be 6 dollars");
  System.out.println ("Enter 6 dollars");
  money = kbd.nextInt();
  while (true){
    if ( money == 6 )
    {
      System.out.println ("Thanks.");
      break;
    }
    else if ( money != 6)
    {
      System.out.println ("You idiot its four dollars");
    }
  }

}
}
}

第二个 if 语句不起作用。如果你们能帮助我，我将不胜感激。

Answer 1

问题是您的 coke 选择代码在 while 循环之外。因此，它从不执行，甚至不检查循环执行中的可乐。

我对您的代码进行了一些格式化，以便于阅读。 :)

顺便说一句，您的 "coke" 条件代码与百事可乐条件不同。我会将它们更改为基本相同，因为它们应该执行相同的基本操作。

将循环更改为：

while (true){     
    if (drink.equals ("pepsi"))
    {
        System.out.println ("That will be 4 dollars");
        System.out.println ("Enter 4 dollars");
        money = kbd.nextInt();
        if ( money == 4 )
        {
            System.out.println ("Thanks.");
            break;
        }
        else
        {
            System.out.println ("You idiot it's four dollars");
        }
    }
    else if (drink.equals ("coke"))
    {
        System.out.println ("That will be 6 dollars");
        System.out.println ("Enter 6 dollars");
        money = kbd.nextInt();
        if ( money == 6 )
        {
            System.out.println ("Thanks.");
            break;
        }
        else
        {
            System.out.println ("You idiot it's four dollars");
        }

    }
    else {
        System.out.println("You didn't make a valid choice, please choose coke or pepsi");
    }

    // Get another input to continue program, here.
}

你真的应该考虑给你的变量命名一些描述它们目的的东西。例如，您的 Scanner 应该命名为：input。这使得它的作用非常清楚，然后暗示如何根据它的对象使用它。

Answer 2

试着把它放在你的 while(true) 语句中。

此外，作为更现实的场景，您可以制作一个包含价格和名称的数组，但这完全是另一个问题

Answer 3

我认为这对你有好处。

import java.util.Scanner;

public class BendingMachineTestWhile {

public static void main(String[] args) {
    String drink;
    int money;
    Scanner kbd = new Scanner(System.in);

    System.out.println(" Pick from the following drinks: \n pepsi \n coke \n gatorade");
    drink = kbd.nextLine();
    while (true) {
        if (drink.equals("pepsi")) {
            System.out.println("That will be 4 dollars");
            System.out.println("Enter 4 dollars");
            money = kbd.nextInt();
            if (money == 4) {
                System.out.println("Thanks.");
                break;
            } else if (money != 4) {
                System.out.println("You idiot its four dollars");
            }

        } else if (drink.equals("coke")) {
            System.out.println("That will be 6 dollars");
            System.out.println("Enter 6 dollars");
            money = kbd.nextInt();
            if (money == 6) {
                System.out.println("Thanks.");
                break;
            } else if (money != 6) {
                System.out.println("You idiot its four dollars");
            }
        } else {
            if (drink.equals("gatorade")) {
                System.out.println("That will be 8 dollars");
                System.out.println("Enter 8 dollars");
                money = kbd.nextInt();
                if (money == 8) {
                    System.out.println("Thanks.");
                    break;
                } else if (money != 8) {
                    System.out.println("You idiot its four dollars");
                }
            } else {
                System.out.println("Your entered drink is not available here so please enter from the list again");
                System.out.println(drink = kbd.nextLine());
            }
        }

    }
}
}

while 循环不适用于两个 if 语句

while-loop isn't working with two if-statements

java

loops

if-statement

while-loop

statements