PHP的循环随机数生成器的问题
[英]php for loop random number generator issue
问题描述
Task: 
任务：
- Use a for loop to build an array (randArray[]) with 50 random integers ranging from 0 - 100. 使用for循环来构建一个数组（randArray []），其中包含50个随机整数，范围从0到100。
- Use a while loop to build a new array (oddArray[]) with all the odd numbers in randArray[] 使用while循环使用randArray []中的所有奇数构建一个新数组（oddArray []）。
- Use foreach loop to print all the odd numbers in oddArray[]. 使用foreach循环可打印oddArray []中的所有奇数。
I just can't understand why this first step for loop doesn't work 我只是不明白为什么循环的第一步不起作用
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Test1-1</title>
</head>
<body>
<?php
$randArray= [];
$value = [];
for ($randArray= 0; $randArray<= 50; $randArray++) {
$value = rand(0, 100)
$randArray[] = $value
}
endfor;
echo ($randArray);
?>
</body>
</html>
2 个解决方案
解决方案1
0 2017-11-21 01:23:59
You can skip a few of them requirements and just handle odd numbers, also rand is not that random.. 您可以跳过其中的一些要求，而只处理奇数，而rand并不是那么随机。
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Test1-1</title>
</head>
<body>
<?php
for ($i= 0; $i<= 50; $i++) {
$value = mt_rand(0, 100);
// odd number
if ($value % 2 != 0) {
echo $value.'<br>';
}
}
?>
</body>
</html>
Edit (some comments with the syntax issues on original code) 编辑（一些有关原始代码语法问题的注释）
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Test1-1</title>
</head>
<body>
<?php
// $randArray set as array, but used as int
$randArray= [];
// $value set as array, but used as int
$value = [];
// $randArray is now set as an int
for ($randArray= 0; $randArray<= 50; $randArray++) {
$value = rand(0, 100) // <-- missing semi-colon + rand not that random, mersenne twister is better
$randArray[] = $value // <-- missing semi-colon + treating $randArray as an array when its now an int, scala value
}
endfor; // whats this?
// $randArray would be an array so you cant just echo it
echo ($randArray);
?>
</body>
解决方案2
0 已采纳 2017-11-21 02:03:45
Abiding by the instructions, you can do this 遵守说明，您可以执行此操作
// random and odd arrays
$randArray = [];
$oddArray = [];
// For loop to get 50 random integers and push to randArray
for ($i = 0; $i <= 50; $i++) {
$value = rand(0, 100);
$randArray[] = $value;
}
// While loop to get odd numbers from randArray and push to oddArray
$x = 0;
while ($x <= 50) {
if ($randArray[$x] % 2 == 1) {
$oddArray[] = $randArray[$x];
}
$x++;
}
// Foreach loop to print all odd numbers
foreach($oddArray as $odds) {
echo $odds . '<br>';
}
Side notes: Use different variables as for loop arguments. 旁注：对于循环参数，请使用其他变量。 That's highly what's causing you errors. 这就是导致您出错的高度原因。 You used randArray again for executing for loop 您再次使用randArray执行for循环
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.