Question

我是第一次学习java的初学程序员。我无法弄清楚如何让程序重复，直到用户输入0。这是问题所在：应用程序应允许用户根据需要输入尽可能多的型号。使用0作为最终用户输入的标记。

输入汽车的型号或0以退出：195 你的车有缺陷。它必须得到修复。输入汽车的型号或0以退出：119 你的车有缺陷。它必须得到修复。输入汽车的型号或0以退出：0

 public class CarRecall
{
// Main method
public static void main(String[] args)
{
    int model; //model number
    Scanner input = new Scanner(System.in);

    do
    {
    System.out.print("Enter the car's model number or 0 to quit: ");
    model=input.nextInt();
    input.close();
    }   
    while (model>0);
    {

        if (model==119)
            {
                System.out.print("Your car is defective. It must be repaired.");
            }
       else if (model==179)
            {
                System.out.print("Your car is defective. It must be repaired.");
            }   
       else if (model>=189 && model<=195)
            {
                System.out.print("Your car is defective. It must be repaired.");
            }   
       else if (model==221)
            {
                System.out.print("Your car is defective. It must be repaired.");
            }
       else if (model==780)
            {
                System.out.print("Your car is defective. It must be repaired.");
            }     
       else 
             System.out.print("Your car is not defective.");
       model=0; 
    }

}

}

Answer 1

如果您想使用while循环，在这种情况下看起来不太必要，请将Model更改为0或添加break

while(Model>0){//add the brace
   //...current if else code
   Model = 0;//or simply break;
}

- 编辑 - （使用do while）

int Model; //model number
Scanner input = new Scanner(System.in);

do{
  System.out.print("Enter the car's model number or 0 to quit: ");
  Model=input.nextInt();

  if (Model==119||Model==179||(Model>=189 && Model<=195)||Model==221||Model==780)
      System.out.println("Your car is defective. It must be repaired.");
  else if(Model>0)
      System.out.println("Your car is not defective.");
}while(Model>0);
input.close();

Answer 2

首先，似乎没有任何理由你应该使用循环。 elements[0].onmousedown = function(){ fireEvent(elements[0], 'onmouseup'); };是一个数字，您可以对其进行检查，但这并不会更改变量function doSomethingOnMouseUp() { console.log('something on mouse up'); } elements[0].onmousedown = function(){ doSomething(); doSomethingOnMouseUp(); }; elements[0].onmouseup = doSomethingOnMouseUp;的值。所以我建议删除整个循环。

如果你想对循环做一些事情，比如在某个时候调整变量model（但还没有实现），你可以使用model关键字来逃避您目前居住的循环：

model

Answer 3

将代码更改为以下内容

        while (true) {
            System.out.print("Enter the car's model number or 0 to quit: ");
            model=input.nextInt();
            if (model == 0) {
                break; // This will break you out of the loop
            } else if (model == 119) {
                System.out.print("Your car is defective. It must be repaired.");
            } else if (model == 179) {
                System.out.print("Your car is defective. It must be repaired.");
            } else if (model >= 189 && model <= 195) {
                System.out.print("Your car is defective. It must be repaired.");
            } else if (model == 221) {
                System.out.print("Your car is defective. It must be repaired.");
            } else if (model == 780) {
                System.out.print("Your car is defective. It must be repaired.");
            } else
                System.out.print("Your car is not defective.");

        }
        // Move the scanner close to outside the loop to avoid `IllegalStateException`.
        input.close();

这将提示用户在每次迭代中输入一个新数字。当用户输入0时，它将转到相应的if条件和break循环。希望这会有所帮助。

为了让循环永远运行，我将while(model > 0)更改为while(true)。这将循环到无穷大，直到您输入＆＃39; 0＆＃39;。

注意：我还没有编译这段代码。只是摘录了你提出的问题。此外，我冒昧地将变量名称从Model更改为model。将变量名称从小写字母开始是一个好习惯。

如何在Java中结束此循环（更新的任务。）

3 个答案: