blocks|key|3859565|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3859566|++++++++<?php
++++++++$n=15;
++++++++for($i=2;+$i<=$n;+$i%2B%2B)
++++++++{
++++++++++++$k+=+1;+++++//assume+that+it+is+prime

++++++++++++for($j=2;+$j<$i;+$j%2B%2B)++//if+$i+is+2,+then+it+won't+enter+the+loop+as+it+will+not+match+the+condition+($j<$i)
++++++++++++{
++++++++++++++++$k=$i%25$j;
++++++++++++++++if($k==0)+
++++++++++++++++++++break;++//if+not+prime,+$k+will+be+set+as+0.+So,+break.

++++++++++++}
++++++++++++if($k!=0)+++//+if+$k+<>+0,+then+it+is+prime
++++++++++++++++echo+"<br+/>"+.+$i."+is+prime";
++++++++}

++++++++?>|code-block|syntax|javascript|3859567|编辑已更新代码以处理“%252”|offset|length|style|BOLD|3859568|entityMap^0|0|0|0|2|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Try this:

<pre><code> &lt;?php
 $n=15;
 for($i=2; $i&lt;=$n; $i++)
 {
 $k = 1; //assume that it is prime

 for($j=2; $j&lt;$i; $j++) //if $i is 2, then it won't enter the loop as it will not match the condition ($j&lt;$i)
 {
 $k=$i%$j;
 if($k==0) 
 break; //if not prime, $k will be set as 0. So, break.

 }
 if($k!=0) // if $k &lt;&gt; 0, then it is prime
 echo "&lt;br /&gt;" . $i." is prime";
 }

 ?&gt;
</code></pre>

Edit
Updated the code to take care of the "2"

blocks|key|5474630|text|试试这个：(使用循环进行白化)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5474631|function+is_prime($p)+{
++++return+($p+>+1)+&&++(($p%252+>=+1)+&&+($p%253+>=+1)+&&+($p%255+>=+1))+%7C%7C++in_array($p,+[2,3,5]);
}|code-block|syntax|javascript|5474632|echo+is_prime(15)；|5474633|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Try this:(whitout using loop)

<pre><code>function is_prime($p) {
 return ($p &gt; 1) &amp;&amp; (($p%2 &gt;= 1) &amp;&amp; ($p%3 &gt;= 1) &amp;&amp; ($p%5 &gt;= 1)) || in_array($p, [2,3,5]);
}
</code></pre>

echo is_prime(15);

blocks|key|140916|text|在它第一次运行的时候，你基本上就是在通过调用以下代码来打破循环：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|140917|if+(something)+{
++++break;
}+else+{
++++break;
}|code-block|syntax|javascript|140918|无论发生什么，它都会崩溃。你需要去掉最后一个突破口。|140919|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You are breaking the loop the first time it's run by calling this basically:

<pre><code>if (something) {
 break;
} else {
 break;
}
</code></pre>

it will break no matter what. you need to take out the last break.

blocks|key|1158447|text|嗯，你的代码有点难以理解；乍一看，它似乎试图通过检查直到N的每个除数来确定素性，但你已经有了我一开始没有看到的外循环……哦，天哪。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1158448|如果你只是想知道某个数字N是否是质数，下面的方法应该是可行的：|1158449|$n+=+15
$prime+=+true;
for+($i+=+2;+$i+<+sqrt($n);+$i%2B%2B)+{
++++if+($n+%25+$i+==+0)+{
++++++++$prime+=+false;
++++++++break;
++++}
}

echo+$n+.+"+is+"+.+($prime+?+""+:+"not")+.+"+prime.";|code-block|syntax|javascript|1158450|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Well, your code is kind of confusing to understand; at first glance it seems as if it's trying to determine primality by checking every divisor up to N, but you've got that outer-loop going on which I didn't see at first... Oh boy.

If you're just trying to figure out if some number N is prime, the following should work:

<pre><code>$n = 15
$prime = true;
for ($i = 2; $i &lt; sqrt($n); $i++) {
 if ($n % $i == 0) {
 $prime = false;
 break;
 }
}

echo $n . " is " . ($prime ? "" : "not") . " prime.";
</code></pre>

blocks|key|1158452|text|<?php
echo+"TEST\r\n";

$n=15;
for($i=2;+$i<=$n;+$i%2B%2B)
{
echo+"I=+$i+\r\n";
for($j=2;+$j<=$i-1;+$j%2B%2B)
++++{
++++++++$k+=+$i%25$j;
++++++++if($k==0)
++++{
++++++++++++break;
++++++++}+else+{+
++++++++++++echo+$i."is+prime+\r\n";
++++++++}
++++++++break;
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1158453|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&lt;?php
echo "TEST\r\n";

$n=15;
for($i=2; $i&lt;=$n; $i++)
{
echo "I= $i \r\n";
for($j=2; $j&lt;=$i-1; $j++)
 {
 $k = $i%$j;
 if($k==0)
 {
 break;
 } else { 
 echo $i."is prime \r\n";
 }
 break;
 }
}
</code></pre>

blocks|key|5474609|text|我认为你的secod+for循环是不正确的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5474610|for($i=2;+$i<=$n;+$i%2B%2B)+{
+++echo+"<br+/>";
+++for($j=2;+$j<=$i-1;+$j%2B%2B)+{
++++++...|code-block|syntax|javascript|5474611|$j的第一个值是2。第一次，$i的第一个值又是2。现在，看看你的第二个for循环代码。第一次会是这样的：|5474612|for($j=2;+$j<=2-1;+$j%2B%2B)+...+//+for($j=2;+$j<=1;+$j%2B%2B)|5474613|而这个条件是完全无效的：2<=1|offset|length|style|CODE|5474614|entityMap^0|0|0|0|0|C|4|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@$M|X|N|Y|O|P]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

I think your secod for loop is incorrect.

<pre><code>for($i=2; $i&lt;=$n; $i++) {
 echo "&lt;br /&gt;";
 for($j=2; $j&lt;=$i-1; $j++) {
 ...
</code></pre>

The first value for $j is 2. And for the first time, the first value for $i is 2 again. Now, look at your second for loop code.
It will be like this at the first time:

<pre><code>for($j=2; $j&lt;=2-1; $j++) ... // for($j=2; $j&lt;=1; $j++)
</code></pre>

And this condition is not valid at all: <code>2&lt;=1</code>

I am just a beginner in PHP. I have tried to write a program for prime numbers, but the result is not correct. I couldn't find the error. How can I correct this? Here is my code:

<pre><code>&lt;?php
$n=15;
for($i=2; $i&lt;=$n; $i++)
{
echo "&lt;br /&gt;";
for($j=2; $j&lt;=$i-1; $j++)
 {
 $k=$i%$j;
 if($k==0)
 {

 break;
 }
 else echo $i."is prime";
 break;
 }

}
?&gt;
</code></pre>

error in php program

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我只是PHP的初学者。我试着写了一个素数的程序，但是结果不正确。我找不到错误。我怎样才能纠正这个错误呢？下面是我的代码：<?php$n=15;for($i=2; $i<=$n; $i++){echo " ";for($j=2; $j<=$i-1; $j++) { $k=$i%$j; if($k==0) { break;

问php程序出错
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