PHP function isPrime() not working [closed] - php

Question

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question appears to be off-topic because it lacks sufficient information to diagnose the problem. Describe your problem in more detail or include a minimal example in the question itself.
Closed 9 years ago.
Improve this question
please help me with code to check if numbers in a table is prime: this is my code below. I used the isPrime function but I get an error where by when I call the function in the table it returns the words "isPime"
<?php
$x="num1";
$y="num2";
if(isset($_POST['Submit'])) {
$start=$_POST['num1'];
$end=$_POST['num2'];
echo "<table width='250' cellpadding='2' cellspacing='4' border='1'>";
echo "<tr><td>Number</td><td>Odd or Even?</td><td>Prime?</td></tr>";
for ($start;$start<=$end;$start++) {
$answer=$start;
$number=$answer;
$check="text";
$num=$answer;
if($number%2==0) {
$check="Even";
} else {
$check="Odd";
}
{ }
echo "<tr><td>$answer</td><td>$check</td><td>
<?php ?>
</td></tr>";
} echo "</table>";
} ?>

Answer 1

You are missing the entire prime check and you aren't even printing anything in your third column.
Also someone seems to have deleted your code in the first EDIT and changed it in the second. I somehow had a copy of the first edit and could make an example.
This is a working example within your code:
<?php
$x="num1"; $y="num2";
if(isset($_POST['Submit']))
{
$start=$_POST['num1']; $end=$_POST['num2'];
echo "<table width='250' cellpadding='2' cellspacing='4' border='1'>";
echo "<tr><td>Number</td><td>Odd or Even?</td><td>Prime?</td></tr>";
for ($start;$start<=$end;$start++)
{
$answer=$start; $number=$answer; $check="text"; $num=$answer;
if($number%2==0)
{ $check="Even"; }
else
{ $check="Odd"; }
$prime = (isPrime($number)? 'Yes':'No');
echo "<tr><td>$answer</td><td>$check</td><td>$prime</td></tr>";
}
echo "</table>";
}
function isPrime($num) {
//1 is not prime. See: http://en.wikipedia.org/wiki/Prime_number#Primality_of_one
if($num == 1)
return false;
//2 is prime (the only even number that is prime)
if($num == 2)
return true;
/**
* if the number is divisible by two, then it's not prime and it's no longer
* needed to check other even numbers
*/
if($num % 2 == 0) {
return false;
}
/**
* Checks the odd numbers. If any of them is a factor, then it returns false.
* The sqrt can be an aproximation, hence just for the sake of
* security, one rounds it to the next highest integer value.
*/
for($i = 3; $i <= ceil(sqrt($num)); $i = $i + 2) {
if($num % $i == 0)
return false;
}
return true;
}
?>

Answer 2

try this
<?php
$x="num1";
$y="num2";
if(isset($_POST['Submit'])) {
$start=$_POST['num1'];
$end=$_POST['num2'];
echo "<table width='250' cellpadding='2' cellspacing='4' border='1'>";
echo "<tr><td>Number</td><td>Odd or Even?</td><td>Prime?</td></tr>";
for ($start;$start<=$end;$start++) {
$answer=$start;
$number=$answer;
$check="text";
$num=$answer;
if($number%2==0)
{
$check="Even";
}
else
{
$check="Odd";
}
if(isPrimeNumber($number))
{
$pirme_status = "Yes";
}
else
{
$pirme_status = "No";
}
echo "<tr><td>$answer</td><td>$check</td><td>$pirme_status</td><</tr>";
} echo "</table>";
}
and PHP function is
function isPrimeNumber($number)
{
$flag = true;
$max_count = ceil($number/2);
for($i=2; $i<$max_count; $i++)
{
if($number%$i==0)
{
$flag = false;
break;
}
}
return $flag;
}
?>