Question

我有这个功能

public static void main(String args[]){

    String first="", second="";
    String x="animal",vegetable,mineral;
    Scanner s=new Scanner(System.in);


    System.out.println("TWO QUESTION!");
    System.out.println("Think of an object, and I'll try to guess it.");

    System.out.println("Is it animal, vegetable, or minaral?");
    first=s.next();

    if (first==x){
        System.out.println("Is it bigger than a breadbox");
        second=s.next();
        if(second=="yes"){
            System.out.println("My guess id that you are thinking of a mouse");
            System.out.println("I would ask you but i really dont care.");
        }else{
            System.out.println("My guess id that you are thinking of a squirrel");
            System.out.println("I would ask you but i really dont care.");

        }

    }else if (first=="vegetable"){
        if(second=="yes"){
            System.out.println("My guess id that you are thinking of a watermelon");
            System.out.println("I would ask you but i really dont care.");
        }else{
            System.out.println("My guess id that you are thinking of a carrot");
            System.out.println("I would ask you but i really dont care.");

        }}else if (first=="mineral"){
            if(second=="yes"){
                System.out.println("My guess id that you are thinking of a Camero");
                System.out.println("I would ask you but i really dont care.");
            }else{
                System.out.println("My guess id that you are thinking of a paper clip");
                System.out.println("I would ask you but i really dont care.");

            }

        }




}

上面的代码给出了错误

未捕获RangeError：超出最大调用堆栈大小

我还想知道在使用

时是否有任何方法可以使用JavaScript切换类

function flicker(length) {
    $("p:nth-child(" + (Math.random() * length) + ")").toggleClass('off');
    setTimeout(flicker(length), Math.random()*1000);
}

我收到错误

未捕获的TypeError：无法读取属性＆＃39;切换＆＃39;未定义的

如何解决这些问题？

感谢。

Answer 1

调试后我发现了2个问题。

Math.random() * length返回一个浮点数，因此您需要进行舍入。
setTimeout可以通过在延迟

length

window.setTimeout（func，[delay，param1，param2，...]）;

function flicker(length) {
  $("p:nth-child(" + Math.round(Math.random() * length) + ")").toggleClass('off');
  setTimeout(flicker, Math.random() * 1000, length);
}

flicker(5)

.off {
  color: white;
  font-weight: bold;
  background-color: black
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<p>1</p>
<p>2</p>
<p>3</p>
<p>4</p>

Answer 2

使用setTimout时，必须将flicker(length)包装在函数中：

function flicker(length) {
  $("p:nth-child(" + (Math.random() * length) + ")").toggleClass('off');
  setTimeout(function(){flicker(length);}, Math.random()*1000);
}

否则它总是被调用，导致类似这样的事情：

function foo(){
  foo();
}
foo();

只会创建一个无限循环，并会导致与您描述的相同的堆栈错误。

Answer 3

问题是因为您通过将结果设置为flicker()而无法传递其引用，从而在无限循环中调用setTimeout。您需要为setTimeout()调用匿名函数。试试这个：

function flicker(length) {
    $("p:nth-child(" + (Math.random() * length) + ")").toggleClass('off');
    setTimeout(function() {
        flicker(length)
    }, Math.random()*1000);
}

未捕获的RangeError：超出最大调用堆栈大小和未捕获的TypeError

3 个答案: