永无止境的循环？

Question

I am trying to display 3 submit buttons on a page at random positions. 我正在尝试在随机位置的页面上显示3个提交按钮。 I have managed to do this. 我已经做到了。 I have now created three functions that generate the coordinates for these buttons and also check that they do not overlap too much with other buttons. 现在，我创建了三个函数，这些函数生成这些按钮的坐标，并检查它们与其他按钮的重叠程度是否过多。

Somewhere in these functions I think I am creating an infinite loop - but I can't see why that would be the case... 在这些函数中的某个地方，我想我正在创建一个无限循环-但我不明白为什么会是这种情况...

Here is the code. 这是代码。 The functions are defined and called in the header. 这些函数在标头中定义和调用。

<?php session_start(); ?>
<html>
    <head>
        <style>
            input[type='submit']{
                position: absolute;
                width: 300;
                height: 50;
                color: white;
                background: red;
            }
        </style>
        <?php 

        $first=array(2,4,8,10);
        $second=array(2,4,8,10);

        $b=rand(0,3);
        $c=rand(0,3);

        $f=$first[$b];
        $s=$second[$c];

        $d=$f*$s;
        $score=$_SESSION["score"];
        $name=$_SESSION["name"];

        function firstxy(){

        $x1=rand(0,500);
        $y1=rand(0,500);
        }

        function secondxy(){
            $x2=rand(0,500);
            $y2=rand(0,500);
            if ($x2-$x1<30 ||$x1-$x2<30){
            secondxy();
        }
            if ($y2-$y1<30 ||$y1-$y2<30){
            secondxy();
        }}

        function thirdxy(){
            $x3=rand(0,500);
            $y3=rand(0,500);
            if ($x3-$x2<30 ||$x3-$x1<30||$x2-$x3<30||$x1-$x3<30){
            thirdxy();
        }
            if ($y3-$y2<30 ||$y3-$y1<30||$y2-$y3<30||$y1-$y3<30){
            thirdxy();
        }}

        firstxy();

        secondxy();

        thirdxy();
        ?>
        </head>
    <body>

        <?php

        echo $name." your score so far=".$score;
        echo "<br>";
        ?>

        <?php echo"Write the answer";?>
        <br>
        <?php echo $f."x".$s."=";?>
    <form method= "post" action="submit.php">
        <input type="number" name=a value="0">
        <input type="hidden" name=b value=<?php echo $f;?>>
        <input type="hidden" name=c value=<?php echo $s;?>>
        <input type="submit" name=submit value=<?php echo $d;?>>

        <input type="submit" id="btn" value=<?php echo $d;?>>
    <input type="submit" id="btn2" value=<?php echo " Wrong answer";?>>
    <input type="submit" id="btn3" value=<?php echo " Wrong answer";?>>
    </form>
    <script>
            var btn = document.getElementById("btn");
//btn.style.top = Math.floor((Math.random() * 230) + 1) + "px";
//btn.style.left = Math.floor((Math.random() * 200) + 1) + "px";
btn.style.top = <?php echo $x1;?>+ "px";
btn.style.left = <?php echo $y1;?> + "px";

var btn2 = document.getElementById("btn2");
//btn2.style.top = Math.floor((Math.random() * 230) + 1) + "px";
//btn2.style.left = Math.floor((Math.random() * 200) + 1) + "px";
btn2.style.top = <?php echo $x2;?>+ "px";
btn2.style.left = <?php echo $y2;?> + "px";

var btn3 = document.getElementById("btn3");
//btn3.style.top = Math.floor((Math.random() * 230) + 1) + "px";
//btn3.style.left = Math.floor((Math.random() * 200) + 1) + "px";
btn3.style.top = <?php echo $x3;?>+ "px";
btn3.style.left = <?php echo $y3;?> + "px";
        </script>

</body></html>

Answer 1

When you are checking for overlap, you should use abs(). 检查重叠时，应使用abs（）。 The following condition will always pass, because one of $x2-$x1 or $x1-$x2 will be negative (therefore less than 30). 以下条件将始终通过，因为$ x2- $ x1或$ x1- $ x2中的一个为负（因此小于30）。

if ($x2-$x1<30 ||$x1-$x2<30)

Try doing something like 尝试做类似的事情

if (abs($x2-$x1) < 30){

永无止境的循环？

问题描述

1 个解决方案

解决方案1
2 已采纳 2015-05-11 19:46:32

永无止境的循环？

问题描述

1 个解决方案

解决方案1 2 已采纳 2015-05-11 19:46:32

解决方案1
2 已采纳 2015-05-11 19:46:32