Question

在这个程序中，我必须一次又一次地在循环中输入温度。当我输入温度一旦它显示正确的显示，但当我再次输入温度时，程序自行终止。

代码是：

import java.util.Scanner;

public class CheckTemperature
{
    public static void main(String [] args) 
    {
        final double TEMPERATURE = 102.5;
        double thermostat;

        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter the substance's temperature: ");
        thermostat = keyboard.nextDouble();

        if(thermostat > TEMPERATURE)
        {
            System.out.print("The temperature is too high. ");
            System.out.print("Turn down the thermostat. ");
            System.out.println("Wait for 5 minutes and check the thermostat again. "); 
            System.out.println("Enter the thermostat here: ");
            thermostat = keyboard.nextDouble();
        }
        else if(thermostat < TEMPERATURE)
        {
            System.out.println("The temperature is low.");
            System.out.println("Turn up the thermostat.");
            System.out.println("Check for 5 minutes and check again.");
            System.out.println("Enter the thermostat here: ");
            thermostat = keyboard.nextDouble();
        }
        else if(thermostat == TEMPERATURE)
        {
            System.out.println("The temperature is acceptable. Check again in 15 minutes.");
            System.out.println("Enter the thermostat here: ");
            thermostat = keyboard.nextDouble();
        }
        else
        {
            System.out.println("Enter the correct temperature value ");
            System.out.println("Enter the thermostat here: ");
            thermostat = keyboard.nextDouble();
        }
    }
}

Answer 1

这是因为你不在循环中。你问温度一次在顶部。然后一旦进入if，那就结束了。

public static void main(String [] args) 
{
    final double TEMPERATURE = 102.5;
    double thermostat;
    Scanner keyboard = new Scanner(System.in);

    while (true) {
        System.out.println("Enter the substance's temperature: ");
        thermostat = keyboard.nextDouble();

        if(thermostat > TEMPERATURE)
        {
            System.out.print("The temperature is too high. ");
            System.out.print("Turn down the thermostat. ");
            System.out.println("Wait for 5 minutes and check the thermostat again. ");
        }
        else if(thermostat < TEMPERATURE)
        {
            System.out.println("The temperature is low.");
            System.out.println("Turn up the thermostat.");
            System.out.println("Check for 5 minutes and check again.");
        }

        else if(thermostat == TEMPERATURE) {

            System.out.println("The temperature is acceptable. Check again in 15 minutes.");
        }

        else{
            System.out.println("Enter the correct temperature value ");
        }
    }
}

小心，暂时不会停止，但你可以随意改变状态。

Answer 2

如果你想一次又一次地获得温度，你必须使用循环。

myJSFunction()

Answer 3

您的代码不是为了“重复”任何AKA迭代任务而构建的。在代码中添加一个循环，使其根据需要重复操作。

这里我们使用while (1==1)创建一个无限循环。此外，我们在检查输入==“X”时添加退出条件，从循环中触发System.exit。这有助于保持从应用程序的优雅退出，而不必强制关闭。

    final double TEMPERATURE = 102.5;
    double thermostat;
    while(true){
           Scanner keyboard = new Scanner(System.in);
           System.out.println("Enter the substance's temperature or press X to exit: ");
           String input = keyboard.next();
           if(input.equals("X")){
              System.exit(0);
           } else{
              thermostat = Double.parseDouble(input);   
              if(thermostat > TEMPERATURE) {
                    System.out.print("The temperature is too high. ");
                    System.out.print("Turn down the thermostat. ");
                    System.out.println("Wait for 5 minutes and check the thermostat again. "); 
                } else if(thermostat < TEMPERATURE) {
                    System.out.println("The temperature is low.");
                    System.out.println("Turn up the thermostat.");
                    System.out.println("Check for 5 minutes and check again.");
                } else if(thermostat == TEMPERATURE) {
                    System.out.println("The temperature is acceptable. Check again in 15 minutes.");
                } else {
                    System.out.println("Enter the correct temperature value ");
                }
           }
    }

Answer 4

Murtaza，你可以使用一个循环或者可以使用任何递归方法并在你的main方法中调用它。你所说的关于双倍不能被引用的错误是由于没有像equals这样的方法（）在Scanner class.besides中，你不应该将int值与double类型变量进行比较。再次，要在if-else块中比较它，你应该使用Double中的equals（）方法，包装类反对传递一个对象作为参数。

if ... elseif一次又一次输入值时出错

4 个答案: