Need help with prime number programm

[jdm95lude]

here is the link to the program it works fine unless you enter in the number 656 it repeats.

http://apollo1.occc.edu/sp0808/ssp_03/PrimeNumber.html

 

The following is my form code.

   <form action="PrimeNumber.php" method="get" >
  	  <p>Enter a number: <input type="text" name="number" id="number"/>
	   <input type="submit" name="submit" id="submit"/></p>
    </form>

 

the following is my php code

 

<?php
// variable n is equal to the id of number on PrimeNumber.html
$PrimeNum = $_GET['number'];

// Checks to see if the number entered is between 1-1000
if ( $PrimeNum == 0 || $PrimeNum >= 1000) 
{
	echo "<p>The number must between 1 and 999. Please try again.</p>";
	echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;

}

// Calculates to check and see if a number is prime. If it is not prime it displays an error message.
       for($i = 2; $i < sqrt($PrimeNum); $i = $i + 2){
              if ($PrimeNum % $i == 0){
		 		 echo "<p>The number you entered was not a prime number.</p>" ;
                     echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
				 // sends the answer to a variable.
				 $notPrime = true;
              }
        }
	// if the number entered is prime it displays a message.
        if ($notPrime != true) {
		echo "<p>The number you entered is prime!</p>";
		echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
	}
?>

[dual_alliance]

I can't test it at the moment, but from what l can see you need to do something like below

 

<?php
// variable n is equal to the id of number on PrimeNumber.html
$PrimeNum = $_GET['number'];

// Checks to see if the number entered is between 1-1000
// Make sure it also checks to see if the number is less then 0 
if ( $PrimeNum <= 0 || $PrimeNum >= 1000) 
{
echo "<p>The number must between 1 and 999. Please try again.</p>";
echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
die(); // Make it so the script stops here and doesn't continue running
}

// Calculates to check and see if a number is prime. If it is not prime it displays an error message.
for($i = 2; $i < sqrt($PrimeNum); $i = $i + 2){
if ($PrimeNum % $i == 0){
echo "<p>The number you entered was not a prime number.</p>" ;
echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
die(); //Like before, we know its not a prime number so there is no reason to continue processing
}else{
echo "<p>The number you entered is prime!</p>";
echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
die(); // like before, except we know now that this is a prime number
}
}
?>

 

Hopefully it works...

[sasa]

your script doesn't right find prime numbers

try number 15

change to

<?php
// variable n is equal to the id of number on PrimeNumber.html
$PrimeNum = $_GET['number'];

// Checks to see if the number entered is between 1-1000
// Make sure it also checks to see if the number is less then 0 
if ( $PrimeNum <= 0 || $PrimeNum >= 1000)
{
echo "<p>The number must between 1 and 999. Please try again.</p>";
echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
die(); // Make it so the script stops here and doesn't continue running
}
//is number 1 prime?
// Calculates to check and see if a number is prime. If it is not prime it displays an error message.
for($i = 2; $i <= sqrt($PrimeNum); $i = $i + 1){
if ($PrimeNum % $i == 0){
	echo "<p>The number you entered was not a prime number.</p>" ;
	echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
	die(); //Like before, we know its not a prime number so there is no reason to continue processing
}
}
echo "<p>The number you entered is prime!</p>";
echo "<p><a href='PrimeNumber.html'>Go Back.</a></p>" ;
?>